Avalanche Activity

Bridger Range
Texas Meadow
Skier triggered thin slab in Bridgers
Incident details include images
Texas Meadow
SS-AS-R1-D1
Coordinates: 45.8406, -110.9330
Caught: 1 ; Buried: 0; Killed: 0

From email on 2/20/2020: "I found some localized instabilities, including some wind whales on the ridge north of Bradley’s... The slide in the photo probably happened naturally this late morning, with a trigger of sun-heated snow from the cliffs above (just west of Texas Hill). It ran approximately 100 meters.

From e-mail on 2/21/2020" "I was a few hundred feet north of it when it released. It was skier-triggered by another party traversing high on that slope. It carried the skier for most of the slide path."


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Cooke City
COOKE CITY
Snowmobiler triggered small avalanche near Goose Lake
Incident details include images
COOKE CITY
SS-AMu-R1-D1.5
Aspect: S
Coordinates: 45.0202, -109.9380
Caught: 0 ; Buried: 0

"A small slide approx 100 ft wide ran about 40 vertical feet. Crown was 3-4 feet deep. Aspect, SE. Trigger unknown however tracks indicate it was likely a snowmobile trigger."


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Northern Madison
Wilson Peak
Natural Avalanches, Wilson Peak
Incident details include images
Wilson Peak
HS-N-R2-D2.5-U
Elevation: 10,200
Aspect: S
Coordinates: 45.3270, -111.3250
Caught: 0 ; Buried: 0

By far the most interesting thing today is an avalanche cycle on the south face of Wilson Peak. Multiple avalanches, some breaking on planar faces, scattered all across the thing. Not sure on depth either- some look quite deep, but I’m wondering if it is the storm snow from the mega-storm 2 weeks ago running on the rock hard surface leftover from the 100+ mph wind event 2.5 weeks ago. We will look more closely with binoculars tomorrow for a better estimate of scale. The slopes were obviously cross-loaded, but we were interested in what exactly made them cycle today (or last night).


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Bridger Range
Flathead Pass
Naturals near Flathead Pass
Incident details include images
Flathead Pass
HS-N-R3-D2.5-O
Elevation: 8,000
Aspect: NE
Coordinates: 45.9684, -111.0210
Caught: 0 ; Buried: 0

Natural avalanche crowns were seen on 2/20/2020 near Flathead Pass that appear to be from the last 2-3 days. They were fresher than crowns that were seen here on 2/9, and these slopes had not slid when the area was visited on 2/9.


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Northern Madison
Buck Ridge
Sledder triggered on Buck Ridge
Incident details include images
Buck Ridge
AMu-R4-D2.5-O
Elevation: 9,300
Aspect: E
Coordinates: 45.1719, -111.3800
Caught: 0 ; Buried: 0

"Went out on a recon to Buck Ridge today. New the dangers and avoided riding open slopes. I had been riding trees most of the day down low and moved up to about mile marker 10 later in the day. Did a side hill through open trees and stopped on top of this slope. Watched it all propagate and slide below me."


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Bridger Range
Wolverine Bowl
Wolverine Bowl natural avalanche, Bridgers
Incident details include images
Wolverine Bowl
SS-N-R2-D2-O
Elevation: 8,400
Aspect: E
Coordinates: 45.8301, -110.9340
Caught: 0 ; Buried: 0

"We came across the debris of a significant slide in one of the steeper lines just north of Wolverine bowl today. There was zero new fallen snow on the debris so it happened sometime this morning before 11:30 a.m. and after the snowfall stopped last night. The multiple crowns looked to be 3-5 feet tall and a large tree has been jammed into the tube ride chute. The toe of the debris is all the way down into the creek at the base of Wolverine. It's possible a large cornice broke off at the ridgeline but we couldn't get eyes on the actual start of the slide. We skinned up and down the debris pile twice while in search mode at around 12:30 but did not pick up a signal. We did not investigate above the pinch of the chute and into the upper part of the slide. The debris pile is quite deep with some damaged trees. We did 6 lines off the ramp over the weekend and did not see any other avalanche activity but obviously some significant wind loading."


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Northern Gallatin
Chestnut Mountain
Natural avalanche on Chestnut Mountain, N. Gallatins
Incident details include images
Chestnut Mountain
SS-N-R4-D2-O
Elevation: 7,000
Aspect: E
Coordinates: 45.6057, -110.8810
Caught: 0 ; Buried: 0

From an observation, "R3-4 D2 avalanche that failed at the ground observed from the Trail Creek Rd. Looked to be several hundred feet wide, couldn’t see the debris, but crown went through lots of trees." 


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Northern Gallatin
Mt Blackmore
Shooting cracks on Mt Blackmore
Incident details include images
Mt Blackmore
Coordinates: 45.4444, -111.0040
Caught: 0 ; Buried: 0

"Toured up Blackmore today, we had shooting cracks under our feet along the north east ridge line."


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Out of Advisory Area
Natural Avalanche Mill Creek, Absarokas
Incident details include images
Caught: 0 ; Buried: 0

"We observed an avalanche on a southeast face while touring in the Absorokas. The avalanche appeared to be naturally triggered earlier in the morning as there were no tracks and my partner and I was the only party in the area today. The avalanche appeared to break on the ground, was about 200 feet wide and ran 600 feet. It was the only avalanche we observed today and was on a relatively shallow slope compared to other regions. We had observed widespread whumpfing and collapses throughout the day."


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Northern Gallatin
Mt Ellis
Collapsing/Whumphing at Bear Canyon
Mt Ellis
Elevation: 6,800
Coordinates: 45.5777, -110.9550
Caught: 0 ; Buried: 0

A group reported: "On Sunday afternoon my partner and I skinned up Bear Canyon and proceeded a half mile south along the ridge from the top of the ski hill. We were considering skiing a treed gully off the ridge down into Shoefelt gulch or skiing the East side of the ridge back into New World Gulch. As we skinned out of the trees (@ 6,800 ft) and out into the meadow above our prospective runs I caused a very audile collapse and it was obvious the wind had done a lot of work moving snow on to the east facing slope. We dug a snow pit, on a west facing slope, about 30 feet down from the ridge. The snowpack in our pit was 95CM deep, we did an extended column test and got an ECTP 13 which failed on the facets near the ground. The slab was ~70 CM. We decided to dig another pit on the east facing slope just across the ridge, making sure not to get too close to gully which looks like a slide path. My partner dug out the majority of the pit and then I joined him to perform another ECT. Just before we isolated our column my partner stepped out of the pit for a second and on he triggered another extremely audible collapse that seemed to have traveled a decent ways across the slope to the north of us, towards the gully. We got an ECTP 12 from this pit, it broke on the facets near the ground and the slab was about 80CM, the snow depth was 100CM. I thought it was interesting that we did not see much cracking while we were skinning or digging our pits, that being said the new snow from this last storm cycle was very dense and it was easy to get it to sheer when we were digging pits but we did not see it collapse. We knew going up that we probably couldn't ski any of what we checked out but had good time looking at the snowpack and skiing with the dogs back down the ridge to Bear Canyon."


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Northern Gallatin
Mt Blackmore
Many natural avalanches on Mt Blackmore
Incident details include images
Mt Blackmore
HS-N-R4-D3-O
Elevation: 9,400
Coordinates: 45.4467, -111.0040
Caught: 0 ; Buried: 0

From an observation on 2/16: "My partner and I skied off the north-north east ridge of Mt Blackmore into the Fox Creek drainage and observed five recent, naturally-triggered avalanches from the recent storm. Three D1 avalanches were scattered across the bowl from the north, northeast and north-northeast aspects next to exposed rock-outcroppings but were too small to capture in a photo. A fourth, D3 R3 avalanche occurred at approximately 9200' on the north aspect that appeared to have broken right at the bedrock and slid approximately 200 vertical feet. Crown looked to be up to 6' deep and 600 feet across. The fifth, D3 R4 avalanche occurred at approximately 9400' on the north-northwest facing aspect in a narrow meadow. Crown was approximately 8' deep and 30 feet across (the width of the meadow). There was rapid wind-loading still occurring on the aspects of the two D3 avalanches covering up their slide paths and we observed significant wind-loading and cracking off the northeast ridge line."

From a separate group on 2/16: "Took a walk up near Blackmore today to take a look at a NE facing aspect. We did not ski our objective because we observed active wind loading and saw many recent avalanches.

The first picture is looking at Alex Lowe Peak from the west ridge of Elephant. There were 5 avalanches clearly visible. I highlighted the crowns/debris paths with red.

The second picture is a close up of the avalanche on the ridge between Elephant and Blackmore on a south aspect. This one was the largest and the most fresh. All avalanches appeared to be naturally triggered from wind loading.

We also saw an avalanche looking north from the NE ridge of Elephant over the east ridge of Blackmore. The avalanche was on a south/southeast facing hill and looked like it broke at the ground. It was pretty sizable. We didn't get a picture, but this looks like it would've been visible from the east ridge of Blackmore looking north."


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Northern Madison
Black Mountain
Collapsing and Cracking on Black Mtn, N Madison
Black Mountain
Coordinates: 45.1628, -111.5290
Caught: 0 ; Buried: 0

While touring up black mountain on Saturday, February 15th 2020, our group heard very loud whoofing on flat ground, collapsing large areas. There was small cracks formed but we were on very low angle slopes. We switched to a back-up plan to get down. A second large whoofing occurred minutes later a short distance away from the first. This time we could feel the snow drop below us by a few inches. We turned around and followed our tracks down. We dug two pits in the vicinity of the collapsing. Two extended column tests produced failures on the same depth hoar at the ground, ECTP 23 and ECTP 16. The latter result was on a pit of at least a meter deep. WE collapsed another flat while skiing down. No other obvious signs of instability were seen.


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Southern Gallatin
Big Horn Peak
Collapsing and cracking in the southern Gallatins
Big Horn Peak
Coordinates: 45.0668, -111.0500
Caught: 0 ; Buried: 0

1. Massive rolling collapse on lower ridge of ascent on Big Horn Peak. Felt like it went out hundreds of yards uphill. No avy activity. Other various collapses while skinning up ridge. 2+ weeks ago the lower ridge only had about 40-50 cms on it, so was not surprised to have that happen after large amounts of loading.

2. Specimen Creek: Heard several whumpfs and saw shooting cracks. No avalanche triggered, but a very unstable snowpack. Some whumpfs traveled farther than others. Very deep snow, fell to about knee height on parts of the trail, even in snowshoes...many shooting cracks and loud, traveling whumpfs as well as shaking ground from settling snow. This was relatively far from avalanche terrain on flat ground. Snowpack very unstable.


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Southern Madison
Taylor Fork
Snowbiker triggered slide in Taylor's Fork
Incident details include images
Taylor Fork
SS-AMu-R2-D2-G
Coordinates: 45.0607, -111.2720
Caught: 1 ; Buried: 0

Slide in Taylor’s fork crown of about 5-6’ and abou100' wide. Human triggered.


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Northern Gallatin
Divide Cirque
Large natural avalanche in Divide Basin, Hyalite
Incident details include images
Divide Cirque
HS-NC-R5-D3-O
Elevation: 10,000
Aspect: E
Coordinates: 45.3934, -110.9690
Caught: 0 ; Buried: 0

1. Observed a sizable deep slab in the Divide basin which appeared to have run within the last few days. The crown extended from the southern end of the basin (northeast facing) through the summit run off Divide (southeast facing)--maybe around a mile. Slab height varied, with the upper end pushing 10 feet and the lower closer to a foot or two. On Divide, the crown approached the summit and debris had run across the flat to the mature trees. Looked like it may have been cornice triggered at the southern end on thinner cover in rocky terrain.

2. Skied the NE shoulder of Divide Peak. Spotted a 1/4 to 1/2 mile long crown spotted along the NE face of Peak 10,024, between Divide Peak and Hyalite Peak. We could not directly determine the crown height, but it was highly visible from our location ~1 mile away.

3. Several large avalanches along the west ridge of divide basin. Appeared to be set off by large cornice drops that propagated across the bowls and stepped down several feet into the snowpack.


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Northern Gallatin
Alex Lowe Peak
Natural avalanche on Alex Lowe Peak
Incident details include images
Alex Lowe Peak
HS-N-R4-D3-O
Elevation: 9,600
Aspect: N
Coordinates: 45.4272, -111.0140
Caught: 0 ; Buried: 0

From an email:

"Near the ridge line of Mt. Blackmore we noticed the East facing slope close to the ridge line was clearly wind loaded and felt collapsing and cracking under our skis. None of those cracks shot out however. We dug a pit on an E- SE facing slope near the ridge line and found no signs of stability, however we ran into a group on our way up who said they dug a pit in a similar area and got an ECTP-22. Looking N-NW from the ridge line we saw some an avalanche crown on the adjacent face (Alex Lowe Peak)."

This is the second time this avalanche path released. See a photo from 1/25/20 HERE.


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Out of Advisory Area
Knowles Peak
2 slides in a week on Knowles Peak, Paradise Valley
Incident details include images
Knowles Peak
HS-N-R4-D3-O
Aspect: N
Coordinates: 45.3048, -110.5430
Caught: 0 ; Buried: 0

1. "Large (presumably natural) avalanche seen on the north face of Knowles. 3ft deep crown, 300ft wide and probably a 100k ft run. Multiple broken trees in the debrisfield. Collapsing on 4" of sugary facets at the ground. Cracking, whoomphing, collapsing, etc found on all aspects on the ascent."

2. Photo is from February 12, Knowles Peak from Moo Creek.


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Northern Madison
Bear Basin
Large natural avalanche in Middle/Bear Basin
Incident details include images
Bear Basin
HS-N-R4-D2.5-O
Elevation: 9,500
Aspect: NE
Coordinates: 45.3344, -111.3720
Caught: 0 ; Buried: 0

We encountered a natural avalanche that appears to have been triggered by a cornice drop. There seemed to be very little fresh snow on the slide surface so we suspect it occurred recently (Feb 14?). The slide occurred on the west side (east facing side) of Bear Basin (pinpoint on the map below). The avalanche was probably 200 feet wide at the top so it clearly propagate across the slope. Crown was 2 to 5 feet tall. We did not hike in there to investigate more carefully. There is a fair amount of trees on this part of the ridge. The picture shows how some large chunks got hung up on trees but we could see that the slide ran across the creek below (almost 1000 vertical feet). We had planned on skiing this slope and/or the open meadow (talus field) a hundred yards north but in light of this observation we turned around, skied back down in Middle Basin in the trees. Side note: we dug a pit earlier on an almost identical aspect (on the Beehive/Middle basin ridge) and obtained ECTN 16 @ 12" below the surface, ECTN 23 @4" below that, ECTN 28 @ 6" below that... Basically some definition between the latest storm layers but no propagation, and a right-side up snow pack. We only dug about 3 feet deep so this pit did not assess the ground level facets, which we figure are wide spread. The natural slide we encountered one ridge over seemed to be a case where a thin area was triggered by a cornice drop.


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Northern Gallatin
Lick Creek
Natural avalanche east of the top of Lick Creek
Incident details include images
Lick Creek
SS-N-R2-D1.5
Aspect: W
Coordinates: 45.5243, -110.9560
Caught: 0 ; Buried: 0

From an observation, "This activity appears to have occurred naturally. No signs of a skin track or skiing. No accurate indication of when it happened, tho appeared fairly recent with no new wind loading." 


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Cooke City
Woody Ridge
Large natural on E side Woody Ridge, Cooke
Woody Ridge
SS-N-R1-D2-O
Elevation: 10,200
Aspect: E
Coordinates: 44.9739, -109.9240
Caught: 0 ; Buried: 0

From an observation, " Climax slid quite large several days ago. We could get a good look at the crown because of the wind, but I’m guessing it was a wind slab that stepped down."

"Climax" is the what the locals call the large east face on Woody Ridge above Hayden Creek.


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Northern Gallatin
Moose Jaw
Natural Avalanche up Moose Jaw, Storm Castle Ridge
Incident details include images
Incident details contain video
Moose Jaw
HS-N-R3-D3-O
Elevation: 9,200
Aspect: N
Coordinates: 45.4494, -111.0760
Caught: 0 ; Buried: 0

Very large avalanche photographed from Gallatin Gateway at the head of Little Bear Canyon. This avalanche likely occurred Saturday or Sunday during the loading event as there is snow on the debris pile. 


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Northern Madison
Buck Ridge
Snowmobile Triggered Slide in McAtee Basin
Incident details include images
Buck Ridge
SS-AMu-R2-D1.5-O
Coordinates: 45.1834, -111.4400
Caught: 1 ; Buried: 0

From observation: "My riding group came upon a group of three riders from out of state digging out a sled. A single rider had been side hilling a steep slope above a deep creek drainage. This is where the trail leaves Third Yellow mule and drops into McAtee. The slope broke with a single rider high on the slope completely burying the sled. The rider managed to stay on top of the debris. The debris was very deep (~12'-15') as it filled in the drainage below."


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Northern Gallatin
Wheeler Mountain
Two large slides on Wheeler Mtn
Incident details include images
Wheeler Mountain
N-R4-D3.5-O
Elevation: 7,900
Aspect: S
Coordinates: 45.5090, -111.0670
Caught: 0 ; Buried: 0

We skied Wheeler via South Cottonwood and found that the two gullies on the East and South East aspects had recently run in their entirety. We could only see the crown on the South East gully but it appeared to have broke on the steepest part of the slope near the top approximate 3-4ft deep and was the width of the gully. Both avalanches ran the full length and width of their gullies, breaking several trees along the way. The East debris pile was about 25ft deep and the South East was 15ft deep. The East rounded the corner into the ravine at the bottom and also ran about 200ft into the forest. A couple larger trees in the path that were not broken had their branches stripped off the bottom 30ft. Interestingly, the narrow meadow between the South East gully and the South East meadow you recently reported slides on has not slid. Also, we had no propagation or collapsing in our pits.


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Northern Madison
Yellow Mountain
Cornice fall triggered soft slab slab in Spanish Peaks
Incident details include images
Yellow Mountain
SS-NC-R3-D2
Elevation: 9,300
Aspect: S
Coordinates: 45.2995, -111.3200
Caught: 0 ; Buried: 0

Cornice fall triggered a soft slab avalanche in the Spanish Peaks on the afternoon of 2/13/2020.

From email: "100 feet wide, slid the new snow layer maybe 2-3 feet deep, made a pretty good runnel, and went close to full path , so it must have entrained a decent amount of snow to travel that far .."


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Northern Gallatin
Garnet Mtn.
Remotely triggered avalanches on Garnet Mtn.
Incident details include images
Garnet Mtn.
HS-ASr-R1-D1-O
Elevation: 8,000
Aspect: NW
Coordinates: 45.4240, -111.2050
Caught: 0 ; Buried: 0

Two avalanches simultaneously remotely triggered by skiers on Wednesday, 2/12/2020. 

From email: "NW aspect at 8000 ft on Garnet Mountain. Two slides, one 15 feet across and one 10 feet across, remotely triggered from 15 ft away. Crown was about four feet deep, triggered on the facets. Didn't travel more than 30 vertical feet.  One slide triggered in dense trees, and both slides traveled into densely treed areas. The snowpack was relatively shallow in the area where slide was triggered. Signs of instability were noted (Back on low angle terrain, after triggering the above slide), Cracks that propagated out 10+feet and were very deep and whomphing."


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Northern Gallatin
Mt Ellis
Collapsing and Cracking on Mt. Ellis
Incident details include images
Incident details contain video
Mt Ellis
Elevation: 8,000
Aspect: E
Coordinates: 45.5777, -110.9550
Caught: 0 ; Buried: 0

"I observed this collapse & propagation as I stepped over some wood in the skinner on the north ridge of Mount Ellis this morning, ~8000’, due East. I was tailing Chabot and his partner, and they had passed this way just minutes before."


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Northern Madison
Deer Creek
Slides triggered in Deer Creek, N. Madison
Incident details include images
Deer Creek
SS-ARr-R1-D1-S
Elevation: 6,700
Aspect: NE
Coordinates: 45.2988, -111.2040
Caught: 0 ; Buried: 0

"Today while touring in the Deer Creek drainage in the Northern Madisons my partners and I noticed many red flags. Wind was strong from the WSW. We had lots of collapsing and some cracking while touring up. We bailed on our main objective, and while returning to the car we triggered a wind slab remotely from the bottom flats of a gulley. A rider in our group began to descend when we felt and heard a large whumph, followed by a 3-5 second loud rumbling before a wind slab on the ridge above (100 yards away) released (SS-ARr-R1-D1-S, NE aspect @ 6700'). It was about 50' wide and 1-2' deep, but didn't have enough energy to run far down the slope. Touchy stuff!"


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Cooke City
COOKE CITY
Small natural and human triggered avalanches in Cooke
Incident details include images
COOKE CITY
SS-N-R2-D2
Coordinates: 45.0202, -109.9380
Caught: 0 ; Buried: 0

1. "...a fresh avalanche observed out there today.  A south aspect around 9400', estimated to be 2-3' deep and 75' wide. Also observed 2 thinner wind slab avalanches that also ran naturally within the last 48 hrs, and were both about 1' deep and 50' wide.  One was a SE aspect, and one was a North aspect." See attached photo Natural avalanche 2-3' deep.

2. "We’ve seen many instances of cracking and wind slab breaks the past two days riding in Cooke, most happened as we sledded past or down the slope. The 1st and 2nd photo are 4” deep breaks at most. The last photo/slide we observed today, S facing slope, not sure how it was triggered, a foot deep crown at most." See attached photos Small 1' deep, Human triggered 1&2.


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Bridger Range
Flathead Pass
Many naturals near Flathead Pass
Incident details include images
Flathead Pass
HS-N-R3-D2.5-O
Elevation: 8,000
Aspect: NE
Coordinates: 45.9684, -111.0210
Caught: 0 ; Buried: 0

We drove to Flathead Pass to look for avalanches from the recent storm and saw widespread crowns that were fresh enough to have ran during the end of the storm. A couple broke in the 3 feet of storm snow, b ut many were 3-5' deep on persistent weak layers.


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Northern Gallatin
Mt Ellis
Collapsing and cracking on Little Ellis
Mt Ellis
Coordinates: 45.5777, -110.9550
Caught: 0 ; Buried: 0

Two parties reported, "Widespread wumphing and cracking on Little Ellis (both on the north side and east facing meadow above)." and "We skinned up the road and planned to ski the eastern meadow below Little Ellis. As soon as we began skinning the meadow, heard, and felt, a significant "whomp" so decided to play it safe and leave the area."


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Bridger Range
Ross Peak
Wind slab avalanche on Ross Peak, Bridgers
Ross Peak
SS-N-S
Elevation: 9,000
Aspect: NE
Coordinates: 45.8586, -110.9560
Caught: 0 ; Buried: 0

"Skied the low angle trees on the NW side of Ross today around 8000 ft. Saw a natural wind slab that had released during the day around 9000 ft. NE aspect, I'd estimate 40 degree slope but I wasn't very close. Moderate to strong winds most of the day."


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Southern Madison
Tepee Basin
Small avalanches in Tepee Basin, N. Madison
Incident details include images
Tepee Basin
SS-AMu
Coordinates: 44.9041, -111.1850
Caught: 0 ; Buried: 0

"...were up in Tepee today, we saw a couple small slides the one below look to be caused from a snowmobiler and we saw one other one high on the Whites peak ridge that looked to be a natural slide or maybe caused from a piece of cornice that broke off.  The rest of the ridge along White Peak also looked to be loaded up..."


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Bridger Range
Truman Gulch
Truman Gulch Natural Deep Slabs
Incident details include images
Incident details contain video
Truman Gulch
HS-N-R4-D3.5-O
Elevation: 8,500
Coordinates: 45.8139, -110.9330
Caught: 0 ; Buried: 0

Avalanche crowns spanned almost the entire ridge of Truman Gulch. They connected, but appeared to run at different times. The most recent was probably last night behind the Patrol lift. Looked very fresh today without any snow on it. In your face/Catch a wave was a day or two old.

All of Jones Crk also went as well as almost every sub ridge towards Ross Peak.


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Northern Madison
McAtee Basin
Snowmobile Triggered Avalanches, McAtee Basin
Incident details include images
McAtee Basin
SS-AMu-R2-D2-O
Elevation: 8,900
Aspect: SW
Coordinates: 45.1771, -111.4350
Caught: 0 ; Buried: 0; Killed: 0

We saw a group of six snowmobilers who said they triggered these slides in McAtee Basin on the left side of the meadow on Saturday, Feb 8. I didn't see tracks up on the hill or sidehill tracks so they may have triggered the slope from the flats below. The debris runs all the way to the bottom of the hill. 


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A child triggered a small avalanche
Incident details include images
SS-AFu-R1-D1
Caught: 0 ; Buried: 0

On private property, this small child triggered a slide and climbed out of the debris, not buried. A very close call! On the heels of this large snowstorm there are possibilities of children getting caught on road cuts or any open hill!


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Northern Gallatin
Portal Creek
Snowmobiler triggered avalanches in Portal Ck, N. Gallatin
Incident details include images
Portal Creek
SS-AMu-R2-D1-I
Coordinates: 45.2890, -111.1410
Caught: 0 ; Buried: 0

A snowmobiler found very touchy conditions in Portal Creek. The new snow easily avalanched on road cuts so they went home.


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Northern Madison
Cedar Mtn.
Natural avalanche on Cedar Mountian
Cedar Mtn.
SS-N
Coordinates: 45.2366, -111.5060
Caught: 0 ; Buried: 0

"Looking out from Big Sky I noticed two (possibly connected) crowns near the ridge top."


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Northern Madison
Beehive Peak
Natural Avalanches West of Beehive Peak
Incident details include images
Beehive Peak
SS-N-R3-D2-I
Elevation: 9,200
Aspect: SW
Coordinates: 45.3539, -111.4050
Caught: 0 ; Buried: 0; Killed: 0

From an obs.: "Large crown in lower meadows west side of beehive basin above jack creek. Both meadows in lower fight of photo went. Southwest aspect. Far right meadow crown is visible and entire face went. Left meadow is hard to see but 1/3 of face slid. I would guess 3-6 foot crown from how visible it was from moonlight."

Another report: "Observed good size crowns from Beehive Basin Road. They were on the west side of the ridge dividing Beehive Basin and Jack Creek. They were not down to the ground but big and wide looked like probably all the recent snow from the storm."


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Northern Gallatin
Wheeler Mountain
Natural avalanches on Wheeler Mtn, N. Gallatin
Incident details include images
Incident details contain video
Wheeler Mountain
SS-N-R3-D2
Elevation: 8,000
Aspect: SE
Coordinates: 45.5097, -111.0820
Caught: 0 ; Buried: 0

"Noted two SS-D1.5/2 naturals (presuming based on lack of any sort of tracks) on Wheeler, typical spots for these conditions, both SE aspect around 8000'."

Dave Zinn dug a snowpit lookers right of the slides in the next path on Wednesday, 2/5, a couple days before the storm. He found weak snow that was ready to avalanche.


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Northern Gallatin
Elephant Mountain
Several avalanches on Elephant Mtn on way to Mt. Blackmore
Elephant Mountain
SS-N-D2-I
Elevation: 8,800
Aspect: NW
Coordinates: 45.4382, -110.9900
Caught: 0 ; Buried: 0

"Noted several avalanches (NW aspect ~ 8800') off of Elephant that traveled quite far into the trees where the summer trail typically runs, all appear to be new snow, D1- D2 in size, average 2' crowns, running on old/new interface from  Feb 2. They appear to have run midstorm, sometime yesterday (photos 1,2,3).  Above 9000', W Winds were crafting fresh wind slabs that were most reactive on a midstorm crystal/density change that buried a layer of stellars ~ 1' deep in shallower spots,  topped with denser snow." 


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Bridger Range
Texas Meadow
Natural 3' storm slabs north of Bridger
Incident details include images
Texas Meadow
SS-N-R3-D2.5-U
Elevation: 7,900
Aspect: E
Coordinates: 45.8406, -110.9330
Caught: 0 ; Buried: 0

We saw three natural avalanche crowns on the afternoon of 2/7/2020. The north half of Texas meadow broke 3' deep and two small pockets in the playground looked to be 3' deep. North of Bridger Bowl on an East aspects at 7,500'-7,900'. They probably occurred within the last 24-36 hrs.


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Northern Madison
Buck Ridge
Natural Avalanche in Muddy Creek, Buck Ridge
Incident details include images
Buck Ridge
SS-N-R4-D2-O
Aspect: NE
Coordinates: 45.1719, -111.3800
Caught: 0 ; Buried: 0

Natural avalanche. North facing slope. Around half mile wide. Photos don't show half of the slide. Broke on the ground facets. Crown was between 3 and 15 feet deep. We didn't get a photo of the deepest crown. Ripped trees out around 5" diameter.


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Northern Madison
Buck Ridge
Human triggered and natural on Buck Ridge
Incident details include images
Incident details contain video
Buck Ridge
SS-AMc-R2-D1.5-I
Elevation: 9,300
Aspect: NE
Coordinates: 45.1719, -111.3800
Caught: 0 ; Buried: 0

We triggered an avalanche in the second Yellow Mule off Buck Ridge on 2/6/2020. It is on a small roll/cornice "in the flats". It broke within the current 2-3' storm snow,18-24" deep.

We also saw a couple natural avalanche crowns 10-18" deep lower down the drainage. I'm sure there were a ton more crowns there, and probably everywhere. through the forecast area. Visibility was limited to 50-100'.


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Northern Gallatin
Mt Ellis
Widespread cracking and collapses on Little Ellis
Mt Ellis
Coordinates: 45.5777, -110.9550
Caught: 0 ; Buried: 0

From observation: "We had cracks shooting around our skis for the entire skin up, and multiple wumphs"


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Northern Madison
Small Natural storm snow avalanches in Gallatin Canyon
SS-N-R2-D1.5-I
Elevation: 6,000
Caught: 0 ; Buried: 0

On the drive to Buck Ridge there were widespread 4-6" deep natural slab avalanches in the storm snow on steep slopes, road cuts and river cuts. Some broke "on the ground", where it was bare ground two days ago. This is some evidence of the upside down nature of this storm.


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Bridger Range
Ross Peak
Natural avalanche near Ross Peak
Ross Peak
SS-N-R3-D2.5
Coordinates: 45.8586, -110.9560
Caught: 0 ; Buried: 0

Large natural avalanche on 2/6/2020 in between Ross Peak and the Throne. Knocked down several trees in the runout. 


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Bridger Range
Texas Meadow
Skier triggered south face Texas meadow
Incident details include images
Texas Meadow
SS-ASu-R3-D2.5-I
Elevation: 7,500
Aspect: S
Coordinates: 45.8406, -110.9330
Caught: 0 ; Buried: 0
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Bridger Range
Saddle Peak
Natural Deep Slab Saddle Peak
Incident details include images
Incident details contain video
Saddle Peak
HS-N-R3-D3.5-O
Elevation: 8,900
Aspect: NE
Coordinates: 45.7943, -110.9360
Caught: 0 ; Buried: 0

A natural 4-8' deep slab avalanche broke on Saddle Peak within the last couple days (2/6 or 2/7) during the current storm. The mountains received 3-5 feet of snow equal to 3-5" of SWE over the last week with more snow in the forecast.


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Northern Gallatin
Hyalite - main fork
Small avalanche triggered under Dribbles Ice Climb in Hyalite
Hyalite - main fork
SS-AFu-R1-D1
Aspect: SW
Coordinates: 45.4472, -110.9620
Caught: 0 ; Buried: 0

"Additionally, on Wedensday my climbing partner and I dug an informal pit because we were concerned with accessing the lower pitches of the dribbles from the point the bootpack ended. We noticed that sugary layer some ways down and went around..when we tried to come up the from the southwest I caused another small slide that was significantly deeper than the one I sent you (2/02); I feel like if it had happened from where people normally cross to climb Dribbles it could have been bad."


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Bridger Range
Saddle Peak
Natural Avalanche in Pinnacles, Bridger Range
Incident details include images
Saddle Peak
SS-N
Aspect: E
Coordinates: 45.7943, -110.9360
Caught: 0 ; Buried: 0
"I took this photo from the highway today just before noon 2/4/20. Looked pretty fresh and not blown in much and the winds were howling. Largest part of the crown looked 6-8' tall right in the center. It connected across a pretty low angle shoulder to pull out the northern bowl."

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Bridger Range
Flathead Pass
Collapsing, cracking and recent natural avalanche in northern Bridgers
Incident details include images
Flathead Pass
Coordinates: 45.9684, -111.0210
Caught: 0 ; Buried: 0

Skiers around Frazier Basin and also at Flathead Pass reported collapsing and cracking as they skied. From Flathead pass, "Lots of collapses and whumphs. Obvious soft slab fractures in new and drifted snow. Saw evidence of point release avalanches on steeper terrain around cliffs. Also saw a crown that appeared to have triggered on the new wind loaded snow, NE aspect. It was approx. 200 feet below a steep rocky ridge."


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Southern Madison
Tepee Basin
Small natural slide in Tepee Basin, S. Madison
Incident details include images
Tepee Basin
SS-N
Coordinates: 44.9041, -111.1850
Caught: 0 ; Buried: 0

This small natural avalanche was seen in Teepee basin on Tuesday, 2/4.


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Northern Madison
Other place
Natural Avalanche in Northern Madison Range
Incident details include images
Other place
SS-N
Aspect: E
Coordinates: 45.6553, -110.5580
Caught: 0 ; Buried: 0

East facing slope seen from Big Sky meadow after Sunday’s storm.


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Cooke City
COOKE CITY
Cooke City Deep Slab Natural
Incident details include images
COOKE CITY
HS-N-R2-D2-O
Elevation: 9,500
Aspect: W
Coordinates: 45.0202, -109.9380
Caught: 0 ; Buried: 0

West aspect around 9500'. Deep slab, mid-slope. Crown estimated to be 4-6' deep.


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Bridger Range
Truman Gulch
Natural Avalanches on the west side of the Bridger Range
Incident details include images
Truman Gulch
SS-N-R3-D2.5
Aspect: W
Coordinates: 45.8139, -110.9330
Caught: 0 ; Buried: 0

1.  "I saw two crowns from the ridge at 1430 today (2/4). One on the lower heavily wind loaded shoulder and one up high in the middle of the path. Not sure if they connected, or were separate. R3-D2.5. 2-4’ deep. The higher one was partially drifted in. My guess is ran yesterday with east winds or early today."

2.  "Saw this looking south from top of the ramp into Jones creek. Looks to be just new snow but couldn’t see the whole crown or the slide path."


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Cooke City
COOKE CITY
Cooke City Wind Slab
Incident details include images
COOKE CITY
SS-N-R1-D1-I
Elevation: 8,600
Aspect: SE
Coordinates: 45.0202, -109.9380
Caught: 0 ; Buried: 0

SEerly aspect around 8600'.  A thinner, smaller storm slab, triggered by dry loose from above.


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Bridger Range
Ross Peak
Natural avalanche near Ross Peak, Bridgers
Incident details include images
Ross Peak
SS-N
Aspect: E
Coordinates: 45.8586, -110.9560
Caught: 0 ; Buried: 0

This avalanche was seen on Tuesday, Feb 4 and likely released on Monday from the wind loading.


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Bridger Range
The Great One
Natural avalanche in Great One, Bridger Range
Incident details include images
The Great One
HS-N-R3-D3.5-O
Elevation: 8,600
Aspect: NE
Coordinates: 45.8926, -110.9620
Caught: 0 ; Buried: 0

Saw this today while skiing. This crown is on a northeast aspect at about 8600 feet. Crown height 6-8 feet. It is mid path in the Great One. It seems to have naturally avalanched on Sunday during the storm, without a cornice trigger, after the wind event. All I can get here is that the slope was overloaded from storm snow, on top of a recently overgrown hard slab. Looks like it initiated higher up and pulled out much deeper below. Definitely a large hard slab avalanche. HS-N-R3-D3.5. Debris made it to the trees in the historic path. Otherwise, northeast aspects are loaded above 8500 feet, and I saw about 14 inches of new at 8000 feet. No loading during the day today. 


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Centennial Range
Reas Peak
Reas Peak - Natural Avalanche
Incident details include images
Reas Peak
HS-R3-D3-O
Elevation: 9,200
Aspect: SE
Coordinates: 44.5358, -111.5130
Caught: 0 ; Buried: 0
It cleared up and I took out my binoculars from our cabin on the west shore of Island Park Reservoir and noticed this huge slide in the bowl south of Reyes peak. Started at the little tree band below the ridge, takes out 1/3 of the bowl, and runs into the Blue Creek terrain trap. I assume this is a natural avalanche.

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Northern Gallatin
Hyalite - main fork
Small avalanche triggered in new snow by ice climber, Hyalite
Incident details include images
Hyalite - main fork
SS-NIu-R1-D1
Aspect: W
Coordinates: 45.4472, -110.9620
Caught: 0 ; Buried: 0

"Climber caused icefall that triggered small avalanche. Thankfully, the bed surface was ice just a few inches down and belayer was just outside the path. Minor entrainment."


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Cooke City
Crown Butte
Snowmobile triggered wind slab Crown Butte
Crown Butte
SS-AMu-R3-D1-S
Elevation: 10,000
Aspect: SE
Coordinates: 45.0525, -109.9620
Caught: 0 ; Buried: 0

R3/D1 wind slab off of the SE side of Crown Butte. Observed from Henderson, and there were numerous sled tracks in the debris/runout.


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Cooke City
Town Hill
Town Hill Avalanche, Cooke City
Incident details include images
Town Hill
SS-NC-R2-D2
Elevation: 8,400
Aspect: SE
Coordinates: 45.0256, -109.9370
Caught: 0 ; Buried: 0

The Nose of Town Hill avalanched on Feb. 1 due to the strong SWerly winds and looked to be triggered by a cornice fall (estimated 2-3' crown, about 75-100' wide. 


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Northern Madison
Cedar Mtn.
Natural avalanche on Cedar Mtn.
Incident details include images
Cedar Mtn.
HS-NCu-R2-D3
Aspect: E
Coordinates: 45.2268, -111.5120
Caught: 0 ; Buried: 0

From Big Sky Ski Patrol: "Also saw a large slide on one of the far ridges of Cedar that was not there yesterday and appears to be cornice triggered."


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Cooke City
Woody Ridge
Wind Slabs on Woody Ridge
Incident details include images
Woody Ridge
SS-N-R1-D1.5-I
Elevation: 9,400
Aspect: E
Coordinates: 44.9937, -109.9160
Caught: 0 ; Buried: 0

Winds Friday night transported snow creating fresh drifts that avalanched naturally over the weekend. We observed two wind slabs that released naturally on the east side of Woody Ridge both appear to be 2-3' deep and 50' wide. 


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Southern Madison
Skyline Ridge
Snowmobile triggered big slides on Skyline Ridge
Incident details include images
Skyline Ridge
HS-AMu-R3-D2.5-O
Elevation: 10,000
Aspect: SW
Coordinates: 44.9205, -111.2300
Caught: 0 ; Buried: 0

From Obs. form: "[Slope] Was marked up previously. We parked out near the bottom and a few guys not in our group start climbing. So we watch them climb. It breaks out. Guy ditches the sled and manages to stay up top. Sled goes down with the slide. Then the snow breaks in 2 other spots creating more slides."

From riders involved: "Yesterday we were the ones in the big sky avalanche. There was no markings on the spot we were climbing. Further down the mountains there were climbs at the same angles of this slope. Thankfully the rider was above the slide when it started and managed to stay on top. Rider walked down the debris and we found the sled lower down in the trees. No injuries."


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Cooke City
Lulu Pass
Human triggered wind slab on Lulu
Incident details include images
Incident details contain video
Lulu Pass
SS-AFr-R2-D2-S
Elevation: 10,000
Aspect: S
Coordinates: 45.0709, -109.9580
Caught: 0 ; Buried: 0

We triggered this avalanche of wind-drifted snow as we approached very carefully from a low angle slope above, on 1/30/2020. This was near Lulu Pass outside Cooke City on a south facing slope at 10,000'. It broke within recently drifted snow, but these slabs could be enough weight to break deeper and wider on sugary layers deep in the snowpack. I initially approached where the cornice was a little steeper (no overhang though), and then I got that funny feeling and backed off and went to safer feeling spot with the intention to dig at the top of the slope. It broke within the recent snow/wind load, and did not step down. It was about 100’ wide x 70’ long x 2-3’ deep.


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Northern Gallatin
Hyalite - main fork
Natural avalanche in wind-loaded snow near Mt Bole, Hyalite
Incident details include images
Hyalite - main fork
SS-N-R2-D2-I
Aspect: SE
Coordinates: 45.4472, -110.9620
Caught: 0 ; Buried: 0

From an observation: "We were up on the ridge off Palace Butte and saw this recent natural released slide. Crown was big in spots. Must have happened sometime over night or in the morning (1/29 or 1/30) perhaps from the recent wind loading. East, southeast facing, on the peak north of MT Bole."


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Northern Madison
Fan Mountain
Large Natural Avalanche on Fan Mtn.
Fan Mountain
G
Aspect: N
Coordinates: 45.2981, -111.5240
Caught: 0 ; Buried: 0

From email: "There was a large avalanche on the north face of Fan.  It is not on the NE Face that everyone skis, but out to the west of the north couloir where there is a major ridge off the summit.  North aspect, estimated at over 1K ft. wide, to the ground with a deep crown.  Likely triggered by cornice fall."


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Cooke City
COOKE CITY
Thin natural wind slabs in Cooke City
Incident details include images
COOKE CITY
SS-N-R1-D1
Aspect: E
Coordinates: 45.0202, -109.9380
Caught: 0 ; Buried: 0

From email (1/30/2020): "2 natural avalanches that ran last night, just west of Cooke City.  Both slides were on easterly aspects around 9500'."


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Northern Gallatin
Mt Blackmore
Small Wind Slab on Mt. Blackmore
Incident details include images
Mt Blackmore
SS-AS-R1-D1-I
Elevation: 9,200
Coordinates: 45.4439, -110.9970
Caught: 0 ; Buried: 0

Snow picked up at Mt. Blackmore with calm to light winds. Someone up there before us pulled out a small wind loaded pocket on the face leaving the basin.


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Bridger Range
Naya Nuki Bowl
Natural Avalanche on Naya Nuki
Incident details include images
Naya Nuki Bowl
HS-N-R2-D2.5-O
Coordinates: 45.8883, -110.9590
Caught: 0 ; Buried: 0

Avalanche crown visible near the top of Naya Nuki Peak in the Northern Bridgers. Estimated max crown depth of 10 ft, approximately 200 ft wide. Photo taken Jan 29th, 2020. Several inches of snow were on the debris, avalanche likely occurred on Monday, Jan 27th. 


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Northern Gallatin
Alex Lowe Peak
Natural on Alex Lowe peak
Incident details include images
Alex Lowe Peak
N-R2-D2-O
Elevation: 9,900
Aspect: N
Coordinates: 45.4272, -111.0140
Caught: 0 ; Buried: 0

A skier saw this slide from the top of Mt. Blackmore on 1/25/2020.


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Northern Madison
Big Sky Resort
Explosive triggered Deep Slab Avalanche at Big Sky
Incident details include images
Big Sky Resort
HS-ABc-R4-D4
Coordinates: 45.2760, -111.4360
Caught: 0 ; Buried: 0

A deep slab avalanche was triggered using explosives on 1/24/2020 in the North Summit Snowfield at Big Sky Resort. 

From email: "The Whale came out close to 10’ deep that tapered to 3’ on the skiers right edge...  It broke on basal facets, thin layer, 1F hard at crown (!) with very hard snow above and below the layer that failed ....  It is likely that the layer that failed had some different characteristics lower in the path that avalanched away- possibly less hard."


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Bridger Range
Ross Peak
Large Collapse near Ross Peak
Ross Peak
Coordinates: 45.8586, -110.9560
Caught: 0 ; Buried: 0

From email: "Went out to Ross Peak with some friends today, and we saw some alarming signs. Snowpack out there was really shallow, similar to the approach to the Throne. We got to the first major clearing at about 7500', which tops out at about 36 degrees at the steepest part. We opted to tuck back in to the trees to try to find a lower-angle route around the slope, but there wasn't really a better option. It is a really short (~50') but wide (~500') slope, and we decided it would be reasonable to cross it one at a time. I was setting the skin track and got a big collapse that scared the shit out of me. For some reason it didn't slide, but I measured a few angles and the area that collapsed was definitely at 34-36 degrees. Probably collapsed an area about 100' across. After I had a chance to clean out my long johns, we turned around and skied back down the skin track."


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Cooke City
Meridian Peak
Natural Avalanche Meridian Peak
Incident details include images
Meridian Peak
HS-NO-R3-D2.5-O
Elevation: 9,800
Aspect: NW
Coordinates: 45.0270, -110.0030
Caught: 0 ; Buried: 0

A large natural avalanche observed on the northwest face of Median Peak on 1/20/2020. Photo: D. Wycoff


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Northern Madison
McAtee Basin
Snowmobile Triggered Avalanche McAtee Basin
Incident details include images
McAtee Basin
HS-AMu-R2-D2-O
Coordinates: 45.1771, -111.4350
Caught: 0 ; Buried: 0

From Instagram: "I watched a snowmobiler set this avalanche off today. Very scary in MT right now."


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Cooke City
Wolverine Peak
Natural Avalanche Wolverine Peak
Incident details include images
Wolverine Peak
HS-N-R3-D2.5-O
Elevation: 10,000
Aspect: SW
Coordinates: 45.0530, -110.0100
Caught: 0 ; Buried: 0

A large natural avalanche observed on the southwest face of Wolverine Peak. Observed 1/20/2020. Photo: D. Wycoff


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Lionhead Range
Lionhead Ridge
Snowmobile Triggered Avalanche Lionhead
Incident details include images
Lionhead Ridge
HS-AM-R2-D2-G
Elevation: 8,800
Aspect: N
Coordinates: 44.7336, -111.3290
Caught: 1 ; Buried: 0

From email: "I wanted to make you aware of a snowmobile triggered slide in Lionhead today. Fortunately, I was not injured, was able to stay completely on top, climbed through the majority of the snow wash after seeing it begin to break, and relatively slowly slid down with the last of the moving snow while still on the machine. When I came to a stop I stood up and was completely free of the snow. Our group is trained in avalanche safety, practiced beacon use prior to leaving town in the morning, were wearing avy gear, and were very fortunate that this ended the way it did.  

A clear reminder that this can happen to any of us and to be careful out there."


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Bridger Range
Texas Meadow
Skier triggered north of Bridger
Incident details include images
Texas Meadow
HS-ASu-R2-D2-O
Elevation: 8,000
Aspect: SE
Coordinates: 45.8406, -110.9330
Caught: 0 ; Buried: 0

A skier was skinning uphill, breaking trail and triggered this avalanche on 1/19/20. They reported, " released a small pocket near texas meadow. Maybe 50 ft wide, 2 ft crown and ran 150 ft....I was not caught and nobody was buried or injured. I was skinning up at about 1130...I got to where it was steeper and as I reached thinner snow near rocks I felt a whump. I took one more step and the pocket released."


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Northern Madison
Cedar Mtn.
Snowmobile triggered on Cedar
Incident details include images
Cedar Mtn.
HS-R3-D2.5-O
Elevation: 10,000
Aspect: NE
Coordinates: 45.2263, -111.4960
Caught: 0 ; Buried: 0

I was on the west side of Pioneer Mtn digging a pit for YC Ski Patrol. I heard a few groups of snowmobiles cruising around the foothills of cedar. I turned and saw two snowmobilers cresting the ridge above the slide pictured as the debris was settling down. The sledders enjoyed the view for a few minutes before turning back the way they came and stumbled upon the slide they had unknowingly triggered. They skirted around the side of the crown and stopped for a few minutes. Based on the height of the rider off his sled, I would estimate the crown to be roughly 10’ at its max height. NE aspect below Cedar


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Southern Madison
Taylor Fork
Collapsing at Taylor Fork
Taylor Fork
Coordinates: 45.0607, -111.2720
Caught: 0 ; Buried: 0

Skied a lap at 44.96854,-111.272761. Two big collapses on the skin back up, and frequent shooting cracks. We were very glad to be skiing low angles.


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Centennial Range
Reas Peak
Snowmobile triggered near Reas Peak
Incident details include images
Reas Peak
HS-AMu-R4-D2.5-O
Coordinates: 44.5477, -111.4860
Caught: 0 ; Buried: 0

Snowmobiler triggered avalanche near Reas Peak on Sunday, 1/19/20. he was able to ride through it uphill.


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Lionhead Range
Lionhead Ridge
Natural cornice triggered Lionhead Ridge
Incident details include images
Incident details contain video
Lionhead Ridge
HS-NC-R2-D2-O
Elevation: 8,900
Aspect: NE
Coordinates: 44.7121, -111.3130
Caught: 0 ; Buried: 0

With only 3" of new snow overnight, a cornice triggered a large avalanche at Lionhead early this morning. It broke 3 to 4 feet deep and propagated on a buried weak layer. This is the only stability test we need today, human triggered avalanches possible and the management strategy is to avoid steep slopes or be clear about your risk tolerance if you are poking into avalanche terrain.


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Bridger Range
Truman Gulch
Collapses and Whumphs west side Bridgers
Truman Gulch
Aspect: W
Coordinates: 45.8535, -110.9700
Caught: 0 ; Buried: 0

From obs: "Took a tour down the ridge dividing Truman and Jones creek Sunday.Snow varied from 12 inches of facets topped with a crust to big solid wind deposits sitting on basal facets to 2 feet of fist and 4 finger snow over a 1 finger crust over more facets. Quite a bit of cracking and whoomphing on westerly and wnw aspects. I avoided the large paths altogether and stayed on the ridge."


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Cooke City
Hayden Creek
Natural Deep Slab Avalanche Hayden Headwall
Incident details include images
Hayden Creek
HS-N-R3-D2.5-O
Elevation: 10,200
Aspect: N
Coordinates: 44.9952, -109.9080
Caught: 0 ; Buried: 0

Spotted the crown on our way down from Ripcurl yesterday, we got a closer look today when we toured into High Hayden. N aspect 10200' 


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Southern Madison
Taylor Fork
Snowmobile triggered in Taylor Fork
Incident details include images
Taylor Fork
SS-AMu-R2-D2-O
Elevation: 9,200
Aspect: NE
Coordinates: 45.0607, -111.2720
Caught: 0 ; Buried: 0

From obs: "2nd hand observation arrived at site about 5 minutes after slide. Triggered by sidehilling snowmobiler but was not caught up in it. looked approximately 50 ft wide 150 ft vertical. Did not appeared to be very deep."


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Bridger Range
Bridger Peak
Cracking/Collapsing on Bridger Ridge
Bridger Peak
Elevation: 8,500
Aspect: SE
Coordinates: 45.7701, -110.9400
Caught: 0 ; Buried: 0

From obs: "Observed whumping and cracking on a slope <25 degrees, E-SE facing. We were on top of the ridge in a safe place, but it was easy to see how a steeper slope could be triggered by someone on more mellow terrain below or off to the side. While traversing the ridge from the M to Bridger we observed multiple (past) cornice collapses that triggered small or no slides, but also a larger slide in the pinnacles."


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Northern Gallatin
Divide Peak
Skier triggered Avalanche north of Divide Peak.
Incident details include images
Divide Peak
SS-ASc-R2-D2-U
Elevation: 9,600
Coordinates: 45.4054, -110.9750
Caught: 0 ; Buried: 0

From obs: "There is a small east facing basin that’s between Divide Peak and Maid of the Mist Basin. While walking along the ridge that connects the two, my partner intentionally broke off a large piece of a cornice, which then triggered two substantially sized avalanches in the basin below. The first avalanche was directly beneath the collapsed cornice with a crown 6-12 inches deep and about 30 ft across. The second avalanche was triggered by the 1st avalanche and had a crown of similar depth but was substantially larger. It was hard to see as the crown travelled uphill and around a corner. The ascpet was E and SE, at the elevation of 9,600ft. The pictures I got are poor, but should give you an idea of the size."


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Northern Gallatin
Wheeler Mountain
Skier triggered small slide Mount Wheeler
Wheeler Mountain
SS-AS-R1-D1.5-O
Coordinates: 45.5097, -111.0820
Caught: 0 ; Buried: 0

From obs: "Skied into to a pillow of snow. I think it started as just sluff but then broke off an avalanche. It was not wide but the crown is estimated at 2 feet. It was not moving fast and I just dug into the bed surface and slowly moved out of it. I was the second skier. The first skiers track did not go as deep as mine. failed on weak facets at the base of a steep roll over."


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Northern Gallatin
Flanders Creek
Skiers triggered 2 large slides Flanders Mtn.
Incident details include images
Incident details contain video
Flanders Creek
HS-ASu-R3-D2-O
Elevation: 9,800
Aspect: NE
Coordinates: 45.4351, -110.9440
Caught: 0 ; Buried: 0

From Obs: "... Our party of two was ascending southwest on a rib with the intention of reaching the ridgeline. At 9800', the upper member of our party triggered a D2.5 with an approximately 100' crown immediately to our south. Crown height appeared 2-3' and the slide traveled approximately a distance of 2,000' and 500 vertical feet down mountain. Within a few seconds, we remote triggered to the north a D3 with an approximately 200' crown. Crown height appeared up to 7' at highest point and slide traveled approximately 300 vertical feet down mountain. The remote triggered slide started approximately 15-20 feet to the north of the location of the lower member of our party, who was approximately 30 vertical feet below the upper member of our party. After the slide the upper member of our party noticed a shooting crack at his elevation. Two skiers and one dog were ascending below us. They observed the avalanche and later mentioned that they were approximately 150 feet in distance from the toe of the remote triggered slide, which completely covered their skintrack. Nobody caught or buried."

From group that was below: "Finished a snow pit at 45.434589, -110.940957. Results were ECT-X, Aspect: 110 deg, Angle: 27 degrees, Depth: 90 cm, Weak layer was above melt/freeze at 60 cm, fist hardness above 62 - 67 cm. Then fairly cohesive newer snow 70 - 90 cm. Weak layer did not budge, even when levered with the shovel.

Knowing there was one party of two ahead of us, we continued to 45.434716, -110.94124 when they triggered slide above. It ran through one of the avalanche paths behind us, that we had crossed. We whooped to see if someone was the trigger and if they were ok, they yelled back all was ok. Our mistake was assuming the party ahead was taking, what we consider to be, the standard route up Flanders, not the subtle ridge that we figured was loaded by the month of west/sw winds We were wrong and were traveling below them but still were traveling in the older trees and not in slide paths, yet another example of why you follow protocol. Anyways I took a bunch of pics. Pin on map is about where they triggered it."


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Bridger Range
Argentina Bowl
Cornice triggered deep slab in Argentina Bowl
Incident details include images
Argentina Bowl
HS-NC-R2-D2-O
Elevation: 8,800
Aspect: NE
Coordinates: 45.7869, -110.9350
Caught: 0 ; Buried: 0

We saw this big natural avalanche at noon on January 18th. It broke late on 1/17/20 or early 1/18/20 after strong wind and new snow (1" SWE) heavily loaded slopes. Photo: GNFAC


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Bridger Range
Hardscrabble Peak
Large natural avalanche near Hardscrabble Peak
Incident details include images
Hardscrabble Peak
HS-N-R3-D3-O
Elevation: 9,000
Aspect: E
Coordinates: 45.9151, -110.9810
Caught: 0 ; Buried: 0

Natural avalanche on 1/17 near Hardscrabble Peak in the Northern Bridgers.

From observation: "At some point between 12:00 and 15:00 a large natural slide occurred in 'October Bowl'. My partner and I saw no tracks in the area. We witnessed a large amount of snow being deposited on that aspect throughout the day. In the photos you can see the crown from 01/16 and the new crown up and to the right."


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Lionhead Range
Lionhead Ridge
Natural Avalanche on Lionhead Ridge
Incident details include images
Lionhead Ridge
SS-N-R2-D2-O
Coordinates: 44.7145, -111.3180
Caught: 0 ; Buried: 0

Natural avalanche observed on 1/17 in Airplane Bowl off of Lionhead Ridge. Broke 2 ft deep and 150 ft wide.


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Cooke City
Henderson Mountain
Two big snowmobile triggered on Henderson Mtn., Cooke City
Incident details include images
Incident details contain video
Henderson Mountain
HS-AMu-R4-D2.5-O
Elevation: 10,000
Coordinates: 45.0448, -109.9330
Caught: 0 ; Buried: 0

Two big avalanches were triggered on Henderson Mountain near Cooke City on 1/16/20. One was huge. The other was still big enough to bury or kill somebody. Nobody was reported caught or injured. Report and photos from a third party that did not witness the slides occur, but were in the area earlier this day and saw the slopes had not slid.

From forecaster site visit: "We parked near the bottom of the debris on the Henderson slide and climbed to the crown. Knife hard wind slab; failed on facets at the ground that were 1F+ hardness (2-4mm). The crown was 5 meters deep (measured) and tapered to 16". There are lots of rocky and thin zones on this slope that were likely the trigger point. Vertical distance was 600', 1000 feet wide, debris was 10' deep."


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Cooke City
Lulu Pass
Natural avalanche north of Lulu Pass, Cooke City
Incident details include images
Lulu Pass
HS-NC-R4-D2.5-O
Elevation: 9,750
Aspect: NE
Coordinates: 45.0813, -109.9600
Caught: 0 ; Buried: 0

This avalanche was a hard slab of wind-loaded snow on a very steep (50 degree) slope with monster cornices above. NE facing, 9700’, and likely ran Wed or Thursday (1/15 or 1/16) deduced from snow on debris. It was cornice triggered and ran on the facets near the ground, propagated 300’ wide, 150’ vertical and 3-6’ deep.


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Bridger Range
Hardscrabble Peak
Large natural avalanche in northern Bridgers
Incident details include images
Hardscrabble Peak
HS-N-R3-D3-G
Elevation: 8,500
Aspect: E
Coordinates: 45.9103, -110.9780
Caught: 0 ; Buried: 0

"... while touring in the Northern Bridgers, my partner and I noticed a very large avalanche that occurred on a North face in "October Bowl" just to the south of Hardscrabble Pk.  We didn't witness it and are unsure of a trigger, but we came in contact with all parties believed to be out there and assume it occurred naturally early this morning from heavy wind-loading. The crown seemed to be 2-3' deep but stepped down to the ground about 200' below the crown. The slide was about 400' in width and ran about 1,000' and we assumed classifications of R3.5 and D3."


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Cooke City
Wolverine Peak
Natural near Cooke
Incident details include images
Wolverine Peak
N-R2-D2-O
Elevation: 9,700
Aspect: SE
Coordinates: 45.0530, -110.0100
Caught: 0 ; Buried: 0

"A south and southeast aspect of Mt. Wolverine around 9,500'-10,000'.  I'd estimate the lower crown to be about 3' deep.  And timing of the event maybe around Jan. 16.?" Photo: B. Fredlund


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Northern Madison
Bear Basin
Bat Ears Couloir and Bear Basin avalanches
Incident details include images
Bear Basin
SS-ASc
Aspect: NW
Coordinates: 45.3453, -111.3750
Caught: 0 ; Buried: 0

From an observation form:

An intentional ski cut at the top of Bat Ears couloir produced a windslab avalanche with a crown 4-8inches deep and ran about as wide as the couloir. We then continued to ski down. Once in the bottom of Bear Basin, we could see a much larger avalanche that looked to be 1-2 days old. Its disjointed crown was some 150ft wide, but it was hard to tell how deep it was, as its crown was fairly far away and partly blown back in. Parts of the slide ran on the ground layer of facets but looked to be the result of wind load.

I do not have pictures of the Bat Ears crown that we triggered. We exited via Bear basin with our tails between our legs, and hope this bad idea on our part can help others make terrain choices this weekend.


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Bridger Range
Argentina Bowl
Skier triggered avalanche near Saddle Peak
Incident details include images
Argentina Bowl
SS-ASu-R3-D2.5-O
Elevation: 8,600
Aspect: E
Coordinates: 45.7869, -110.9350
Caught: 1 ; Buried: 0

Skier triggered avalanche in Argentina Bowl on Saddle Peak. Observed from the highway. Occurred during the day on Wednesday, 1/15/2020.

From e-mail: "Skiers triggered two separate slides on south Saddle this afternoon. we witnessed the smaller slide to the lookers right of the big slide, the bigger one happened later apparently... The first smaller slide was caused by a ski cut near the trees, fracture was about 2 feet, soft slab that seemed to run on a thin sun crust. below the sun crust was also very weak and sugary. Not sure when the second skier went farther out and triggered the whole bowl, but they got lucky!!"


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Cooke City
Mineral Mountain
A couple of thin, natural avalanches near Cooke City
Incident details include images
Mineral Mountain
SS-N
Elevation: 9,600
Aspect: SE
Coordinates: 45.0303, -109.9980
Caught: 0 ; Buried: 0

Photo attached of a couple thin, natural slab avalanches near Cooke this morning.  SE aspects of Mineral Mtn., around 9,600'.


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Southern Gallatin
Big Horn Peak
Whumphing at Big Horn Peak, S. Gallatin Range
Big Horn Peak
Elevation: 7,800
Coordinates: 45.0668, -111.0500
Caught: 0 ; Buried: 0

From an email:

HS above 8000' is 80-100cm. Down low its pretty thin and punchy but we were able to link together supportable sections for great ankle deep powder to the valley floor.  Around 7800' we got one whoomph while skiing out.


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Northern Madison
Beehive Basin
Beehive East Ridge
Incident details include images
Beehive Basin
L-AS-R1-D1-I
Elevation: 9,000
Coordinates: 45.3250, -111.3830
Caught: 0 ; Buried: 0

Small skier triggered loose dry avalanche observed on a south facing slope at about 9000' on the ridge separating Beehive and Middle basins.


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Cooke City
Mt Fox
Large natural avalanche on Mt. Fox, Cooke City
Incident details include images
Mt Fox
HS-N-R4-D3-G
Aspect: NE
Coordinates: 45.1212, -109.9300
Caught: 0 ; Buried: 0

From an email:

From afar, observed a large R4/5 D3, to the ground, off of the entire NE shoulder of Fox Mtn. (see attached photo) as well as a couple of scattered R1/D1 wind slabs on upper elevations on E/NE aspects. 


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Southern Madison
Taylor Fork
Snowmobile Triggered Avalanche in Taylor Fork
Incident details include images
Taylor Fork
SS-AMu-R1-D1-G
Aspect: E
Coordinates: 45.0607, -111.2720
Caught: 0 ; Buried: 0

A small but relatively deep avalanche triggered by a snowmobiler on Tuesday, 1/14/2020. 30 ft wide. Ran 20 vertical feet. This avalanche broke to 2-3 ft deep, to the ground. This is the second time this year this slope has slide, it also avalanched in mid-December.


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Bridger Range
BRIDGER RANGE
18-24" Wind Slab North of Bridger Bowl
Incident details include images
BRIDGER RANGE
SS-AS
Coordinates: 45.8512, -110.9480
Caught: 0 ; Buried: 0

Skier triggered wind slab reported north of Bridger Bowl on 13 January. Photo: B. Henry


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Cooke City
Meridian Peak
Remote Trigger Meridian Peak
Incident details include images
Meridian Peak
SS-ASr-R3-D2-I
Elevation: 8,370
Aspect: S
Coordinates: 45.0270, -110.0030
Caught: 0 ; Buried: 0

We toured into Meridian today. On our approach we remote triggered a soft slab on the climber’s left (west) side of the crux approach slope. It was 50’ wide, ran 150’, and the crown was about 12-15”. It was a south aspect at 8370’ with a ~40 degree start zone. The storm slab ran on a crust.


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Northern Madison
Buck Ridge
Natural Avalanches on Buck Ridge
Incident details include images
Incident details contain video
Buck Ridge
N-R2-D2-O
Elevation: 9,150
Aspect: NE
Coordinates: 45.1858, -111.4170
Caught: 0 ; Buried: 0

We could see a few avalanches that likely broke yesterday on 1/11/2020.

  1. The wind pillow under the large cornices in 2nd Yellowmule broke. It looked like just the wind load, vs breaking at the ground. 200' wide x 150' vertical 1-2 feet deep.
  2. In the 3rd Yellowmule  a wind-loaded slope avalanched 200' wide, 75' vertical and 2 feet deep. It broke on a layer of weak, faceted snow near the ground.
  3. Off the east ridge of MacAtee Ridge we could make out 3 slab avalanches that released naturally. Only one looked big enough to bury a person.

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Cooke City
Daisy Pass
Snowmobile Triggered Slide on Chimney Rock
Incident details include images
Daisy Pass
SS-AM-R2-D2
Aspect: SW
Coordinates: 45.0497, -109.9640
Caught: 0 ; Buried: 0

Snowmobile triggered avalanche on the WSW face of Chimney Rock near Daisy Pass. Likely triggered morning of 1/10/2020.


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Northern Madison
Yellowstone Club
YC Patrol triggered avalanche to ground
Incident details include images
Yellowstone Club
SS-AE-R3-D2
Elevation: 8,500
Aspect: NE
Coordinates: 45.2311, -111.4410
Caught: 0 ; Buried: 0

Yellowstone Club Ski Patrol triggered a slide with explosives, breaking at the ground, during avalanche mitigation work on Friday, 1/10/2020.

From Yellowstone Club Patrol: "It’s a NE facing slope at 8500’ ... got an avalanche to release on an old layer of well defined surface hoar (perhaps from mid-December). In some areas it stepped to ground. The crown was 2-4’ deep and the avalanche was recorded as R3/D2. The avalanche slid to the bottom of the runout and placed 3-12’ of snow in the road and completely blocked the road. This was a relatively large slide for this particular path this early in the season."


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Bridger Range
Saddle Peak
Skier triggered slide on Saddle Pk
Saddle Peak
SS-ASu-R1-D2-I
Elevation: 8,900
Aspect: NE
Coordinates: 45.7943, -110.9360
Caught: 0 ; Buried: 0

A skier in the Slushman's lift line at 12:30 watched a skier trigger a soft slab above the first cliffs on the face of Saddle. They skied out and got lucky. It was 150' wide propagated towards the skyline ridge.


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Northern Madison
McAtee Basin
Natural Avalanche near Buck Ridge
Incident details include images
McAtee Basin
SS-N-R2-D1.5
Coordinates: 45.1771, -111.4350
Caught: 0 ; Buried: 0

Natural avalanche observed west of McAtee Basin, near Buck Ridge. Likely broke on 1/9/2019 or morning of 1/10/2019.


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Southern Madison
Hebgen Lake
Avalanche on Hebgen Lake Road Cut
Incident details include images
Hebgen Lake
SS-ASr-R1-D1-O
Elevation: 6,600
Aspect: SW
Coordinates: 44.8381, -111.3430
Caught: 0 ; Buried: 0
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Northern Madison
Middle Basin
Windslab in Middle Basin
Incident details include images
Middle Basin
SS-R1-D1
Coordinates: 45.3374, -111.3810
Caught: 0 ; Buried: 0

Small windslab on the apron of the Buttcrack Chute in Middle Basin. Likely broke 1/9 or morning of 1/10/2020.


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WASHBURN RANGE
Avalanches in YNP
Incident details include images
WASHBURN RANGE
SS-R1-D1
Elevation: 7,500
Aspect: E
Coordinates: 44.8101, -110.4940
Caught: 0 ; Buried: 0

From email on January 10th: "2 recent slides from near the Blacktail Plateau from yesterday and today.  Both were wind loaded, easterly aspects, and elevations were about 7,500'."


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Cooke City
Town Hill
Skier triggered avalanche on Town Hill, Cooke City
Incident details include images
Town Hill
SS-ASc-R0-D1
Elevation: 8,200
Aspect: S
Coordinates: 45.0256, -109.9370
Caught: 0 ; Buried: 0

Skier triggered slide on Town Hill.  A southerly aspect at 8200'.  It was triggered with a ski cut, and no one was caught.  Specs: about 2' deep, 50' wide, and it ran about 75' vertical.


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Cooke City
Miller Ridge
Natural Avalanche on Miller Ridge
Incident details include images
Miller Ridge
SS-N-R2-D2
Coordinates: 45.0423, -109.9650
Caught: 0 ; Buried: 0

Natural avalanche on a steep east facing windloaded slope of Miller Ridge. Photo taken 1/10/2020. Likely broke Tuesday or Wednesday during the storm.


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Northern Madison
Yellow Mountain
Skier triggered avalanche in N. Madison
Yellow Mountain
SS-ASu
Elevation: 9,200
Aspect: NE
Coordinates: 45.2995, -111.3200
Caught: 0 ; Buried: 0

From an email:

9200 ft - NE Aspect CT13-Q2 •Wind-loading of leeward N & E facing slopes •10-20 mph winds

My partner and I skied the apex of the ridge to avoid avalanche terrain, he triggered a soft slab, 1.5 ft deep, off the top of the ridge, crown 100ft wide, ran 300 ft down slope. Collapsing observed on the lower tree portions of the exit out Trail Ck.


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Northern Madison
Middle Basin
Middle Basin Cornice Fall
Incident details include images
Incident details contain video
Middle Basin
C-AOu-R2-D2-I
Elevation: 9,200
Aspect: SE
Coordinates: 45.3237, -111.3810
Caught: 0 ; Buried: 0

Large cornice collapse in Middle Basin. The cornice broke 10' back from the edge, 6-7' deep, and ran 800-1000' vertical. The collapse was triggered by a dog in another party.

The crown depth in the cornice was 6-7', but the snow rode up onto the interface and gouged 24" of snow out. 


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Northern Gallatin
Flanders Creek
Small avalanches in Hyalite on Flanders and the Mummy
Incident details include images
Flanders Creek
SS-N-D1-O
Aspect: N
Coordinates: 45.4402, -110.9310
Caught: 0 ; Buried: 0

From an email:

"Beauty of a day up in Hyalite so long as you didn't mind the wind. The SW/W winds were cranking and clearly transporting snow all day at ridgetop (photo attached). Above 7500' we consistently found ~20cm of new snow from the storm earlier in the week on on top of a thin soft slab over small (but well developed) near surface facets. - A quick pit at 8900' on a protected 30 degree East aspect yielded no obvious slab and no propagation in tests but did show fractures along the new snow/old snow boundary and consistent deeper collapses in the buried crust-facet-sandwich. - We did notice a few recent natural avalanches on wind loaded north aspects in aprons below large cliffs and underneath large cornices (D0.5 - D1, max depth 1m, max width 30m) but these seemed to mostly be small soft storm slabs. - One recent crown near the top of the Mummy (30cm deep) looked to have run naturally on an old crust layer (photo attached) - We avoided slopes greater than 35 degrees and wind-loaded open slopes today and experienced no cracking, collapsing or avalanching where we travelled. - The next front rolled in rather quickly at 3pm with S2+ snowfall and ripping winds throughout the valley."


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Bridger Range
Bridger Bowl
Bridger patrol triggered deep slab
Incident details include images
Bridger Bowl
HS-ABc-R4-D3-O
Elevation: 8,500
Aspect: NE
Coordinates: 45.8156, -110.9230
Caught: 0 ; Buried: 0

This slide was triggered by Bridger Bowl ski patrol during control work on Saturday (1/4/2020) on "The Drain". This is a heavily wind loaded slope on the south end of the ski area adjacent to the backcountry (Saddle Peak). It shows deeply buried persistent weak layers from early October and November were pushed to a breaking point by the recent snow and wind.


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Bridger Range
Ross Peak
Shooting cracks at Ross Peak, Bridgers
Ross Peak
Coordinates: 45.8586, -110.9560
Caught: 0 ; Buried: 0

From an email:

"Skied from Bracket creek to the east facing glades below Ross Peak. At lower elevations very thin snowpack. As we got higher, snow had been significantly wind effected. Experienced several shooting cracks. At 8000 ft, snow was still only 50-75cm deep with variable wind slab. Did not dig a full pit, but hand shear tests showed the wind slab was very poorly bonded to the facets beneath. Winds were swirling and increased from calm to strong throughout the day. Blowing snow mostly filled in our tracks within about 30 mins."


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Cooke City
Scotch Bonnet
Cooke City lots of settling & cracking of the snow
Scotch Bonnet
Coordinates: 45.0566, -109.9510
Caught: 0 ; Buried: 0

Lots of setteling ......and lots of Cracking in the new snow interface.


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Northern Madison
Buck Ridge
Three snowmobilers caught in very large slide on Buck Ridge
Incident details include images
Incident details contain video
Buck Ridge
HS-AMu-R4-D3-G
Elevation: 9,300
Aspect: NE
Coordinates: 45.1719, -111.3800
Caught: 2 ; Buried: 2; Killed: 0

From one of the riders caught in the slide, "The 3 persons involved were traveling across the slope about 20-30 yards up from the tree line parallel to the ridge line in the slide area when it broke, not high marking and not traveling uphill. One rider did increase his elevation while traveling across the slope but was never more than 1/4 of the way up when the slide was triggered."


@carter.olson, "I witnessed three snowmobilers trigger and get caught in an avalanche at second Yellowmule (Buck Ridge) at 12:40PM today. The lead snowmobiler triggered the avalanche while descending from his high mark with the other two snowmobilers below him. The lead snowmobiler was able to run out the avalanche to a degree and made it to the edge of the runout at the bottom. The other two snowmobilers were pointed uphill when the avalanche was triggered and shot into the trees when attempting to outrun the avalanche. The female was buried to her torso and the male was buried to his waist. Both sleds were buried about three feet under the debris. The Avalanche propagated about 1500ft wide. Luckily everyone involved was not harmed, just a broken a arm on one of the buried sleds.
Luckily I was able to jump into action, yelling “Avalanche, Avalanche, Avalanche” grabbing everyone in my group’s attention. Then I told everyone to get their beacons out and put them to search and get to where we last saw the snowmobilers. On our way to the last point of sight of the snowmobilers, they all screamed out they were ok."


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Northern Madison
Big Sky Resort
Deep slab avalanches triggered by Big Sky patrol
Incident details include images
Big Sky Resort
HS-AEc-R3-D2.5-O
Elevation: 10,000
Aspect: SE
Coordinates: 45.2760, -111.4360
Caught: 0 ; Buried: 0

"We triggered 3 significant persistent slabs with explosives on the south face, all in areas that had been rapidly loaded by last night’s winds.  Castro’s shoulder, Upper Rodeo and Jailbait (HV) all succumbed to the load and failed 3-6’ deep on the ice crust 30-60 cm off the ground and showed impressive propagation.  One significant new snow slide in Lenin failed 4-5’ deep just involving snow that had been deposited since this storm began." - BSSP


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Northern Madison
Beehive Basin
Avalanche in Beehive
Incident details include images
Beehive Basin
SS-R3-D2-O
Elevation: 8,600
Aspect: SW
Coordinates: 45.3407, -111.3910
Caught: 0 ; Buried: 0

From e-mail: "Toured in Beehive today. Good snow but very windy. Pics show a large avalanche in the area where “Going Home” ends. Lighting was difficult so not that clear. There was a smaller slide just to the right of the picture and one chute from the end of “Going Home”.

The slide pictures took out some small trees. I was surprised how far into the low angle the debris ran.

Hard to know if this was skier triggered but there were one set of tracks coming down Going Home." Photo: A. Crawford


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Bridger Range
Saddle Peak
Large Natural on Saddle Peak
Incident details include images
Saddle Peak
N-R3-D2.5-O
Elevation: 9,000
Aspect: E
Coordinates: 45.7943, -110.9360
Caught: 0 ; Buried: 0

Seen from the road Friday morning (1/3). Likely ran within last 12-24 hrs.


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Bridger Range
BRIDGER RANGE
Natural slides and collapsing in Bridger Range
Incident details include images
Incident details contain video
BRIDGER RANGE
SS
Coordinates: 45.8512, -110.9480
Caught: 0 ; Buried: 0

Skiers saw a recent natural avalanche near Fairy Lake on 1/3/20.

Ski patrol saw recent natural avalanche debris in Truman Gulch behind Bridger Bowl on 1/3/20.

These slides may have happened early morning on 1/3/20 or late 1/2/20.

Skiers had widespread collapsing and a a few "whumphs" of the snowpack at The Throne.


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Northern Madison
Yellow Mountain
Natural Avalanche on Yellow Mountain
Incident details include images
Yellow Mountain
N-R2-D2
Elevation: 9,000
Aspect: SE
Coordinates: 45.2995, -111.3200
Caught: 0 ; Buried: 0

A large avalanche crown was seen on Yellow Mountain from the Big Sky meadow village on the morning of 1/4/2020. It reportedly spanned across the entire avalanche path


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Cooke City
COOKE CITY
Many small, natural avalanches outside Cooke City
Incident details include images
Incident details contain video
COOKE CITY
SS-N-D1.5
Coordinates: 45.0202, -109.9380
Caught: 0 ; Buried: 0

Multiple reports from today:

1. Noted 2 natural slab avalanches today.  One was a north facing aspect of Mt. Republic, approx. 8500', and estimated to be about 1-2' deep and 40' wide.  And the other was on Town Hill, a SE aspect about 7,800' (photo attached).

2. No camera with me, but observed a natural on a steep roll-over E. of The Gully on Town Hill. N. aspect ~ 8,000'. New snow not well bonded to old snow surface.

3. Saw a small natural happening on the Ozarks. Small naturals on E Republic. Storm snow D1 to 1.5. Wind drifts cracked consistently and we had one localized collapse. The storm and winds slabs were very reactive.
 


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Northern Gallatin
Mt Blackmore
Small skier triggered avalanche near Mt Blackmore Trail, Hyalite
Mt Blackmore
ASu-R0-D1
Elevation: 9,000
Aspect: NW
Coordinates: 45.4473, -110.9990
Caught: 0 ; Buried: 0

From an email:

"Also observed a recent slide on the northwest face of elephant, at about 9000 feet, in the second elephant glade along the blackmore trail. Wind pocket looked to be triggered by a skier on their way out, maybe 30 feet wide, ran for a 80 feet. Looks like they stayed high, just below a rock band on their exit and cut the wind slab."


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Northern Gallatin
Maid of the Mist
Skier remotely triggered a small wind slab up Hyalite
Incident details include images
Maid of the Mist
SS-ASr-R0-D1-I
Coordinates: 45.4164, -110.9700
Caught: 0 ; Buried: 0

From an email: "Remotely triggered this small wind slab while skinning into the Maid of the Mist basin. Throughout the day I continued to encounter other small, reactive wind slabs and strong winds."


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Northern Gallatin
Flanders Creek
Ice climber hit by loose snow avalanche on Killer Pillar, Hyalite
Flanders Creek
L-N
Aspect: NE
Coordinates: 45.4402, -110.9310
Caught: 0 ; Buried: 0

From an email:

"Got hit by a pretty decent loose snow avalanche from above while topping out on Killer Piller up Flanders. Had a decent stance so I was able to hold on. Also observed more than a few coming down gullies on the other side of the drainage. It was lightly snowing all day and dead calm in the drainage, so presumably winds were cranking on the ridgetop."


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Out of Advisory Area
Remote triggered 6' deep in Tobacco Root Mtns
Incident details include images
HS-ASr-R3-D2.5-O
Aspect: N
Caught: 0 ; Buried: 0

Party of three skiers remote triggered avalanche with at least 6' crown off N face of Mt Porphry along rockband near summit. They had dug three pits dug on NE face ascending Mt Porphry indicating increasing stability and no clean propagation. Approx 150-210 cm deep snowpack. See attached photo.


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Cooke City
Henderson Mountain
Two large, deep avalanches on Mt. Henderson near Cooke
Incident details include images
Incident details contain video
Henderson Mountain
HS-AMu-R2-D2-O
Elevation: 10,000
Aspect: NE
Coordinates: 45.0524, -109.9450
Caught: 0 ; Buried: 0

Skiers reported: "Two new [trigger unknown] avalanches on the east side of Henderson today. The first photo is from this morning (12/27/19) around 11:00. The second one appears to be much deeper and I didn't notice it until I rode back by around 2:30, so it might have occurred while I was out skiing or I just missed it this morning."

From Dave and Doug's investigation on 29 Dec:

1. The lookers left avalanche was the deepest at 6' deep of Hard Slab. Estimated 150' wide and 300' vertical. It broke on facets near the ground.

2. The avalanche to the right was 3' deep and also broke on facets near the ground. It too was heavily wind-loaded. Estimated 250' wide and 300' vertical.


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Cooke City
Daisy Pass
Snowmobiler triggered avalanche near Daisy Pass, Cooke City
Incident details include images
Daisy Pass
HS-AMu-R2-D2-O
Elevation: 10,000
Aspect: NW
Coordinates: 45.0497, -109.9640
Caught: 0 ; Buried: 0

A snowmobiler triggered this avalanche. He was not caught. This slope is below Chimney Rock next to Daisy Pass. It is a heavily wind-loaded slope and failed on facets at the ground.


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Cooke City
Henderson Mountain
Wind Slab avalanche near Cooke City
Henderson Mountain
SS-N-R1-D2-U
Elevation: 10,000
Aspect: E
Coordinates: 45.0524, -109.9450
Caught: 0 ; Buried: 0

From email (12/26): "Saw some recent avalanche activity on steep east facing wind loaded slopes of Henderson and Sheep. Both avalanches looked recent and were "pockets" going in the D2, R1.5 range about 1.5-2.5' deep."


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Lionhead Range
Lionhead Ridge
Natural Avalanches near Lionhead
Incident details include images
Lionhead Ridge
SS-N-R1-D2-O
Elevation: 9,000
Aspect: E
Coordinates: 44.7145, -111.3180
Caught: 0 ; Buried: 0

Two natural avalanches near Lionhead Ridge likely broke during the storm on Christmas Eve. One slide appears to have broken on a weak layer in the middle of the snowpack, while the other only involved the new snow. Both were less than 100 ft wide and ran a couple hundred feet. They were on south east and northeast facing slopes at around 9000 ft.

Photo: GNFAC


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Northern Madison
Buck Ridge
Small Slide in 2nd Yellowmule
Incident details include images
Buck Ridge
HS-R1-D1-I
Coordinates: 45.1719, -111.3800
Caught: 0 ; Buried: 0

Small avalanche in 2nd Yellowmule. Likely broke during storm on 12/24. Less than a foot deep but ~150 ft wide.


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Northern Gallatin
Flanders Creek
Large Collapse on hard wind slab in Hyalite
Flanders Creek
HS-AF-O
Elevation: 7,900
Aspect: NW
Coordinates: 45.4388, -110.9260
Caught: 0 ; Buried: 0

Ice climbers had a very hard wind slab collapse, crack and "whumph" while approaching a climb in Flander's drainage. Winds were blowing strong and drifting snow. They noted their tracks were filled in when they left, and fresh drifts cracked when isolated.


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Bridger Range
Fairy Lake
Human triggered hard wind slab near Fairy Lake
Incident details include images
Fairy Lake
HS-AU-R4-D2-O
Coordinates: 45.9043, -110.9580
Caught: 0 ; Buried: 0

Riders near Fairy Lake reported this slide on Saturday 12/21. Photo: @turbo_dieshall


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Cooke City
Hayden Creek
Large natural avalanche near Cooke City
Incident details include images
Hayden Creek
HS-N-R2-D2.5-O
Elevation: 9,800
Aspect: NE
Coordinates: 44.9918, -109.9150
Caught: 0 ; Buried: 0

Skiers with a level 2 class near Cooke City reported: "...toured into East Hayden today with the Level 2 course. We noticed some recent natural activity on the S end of the Climax path (see photo). 

We dug on a N aspect... around 9500'. HS 100 cm, CT22 SP down 60 cm on FC above the Thanksgiving crust. ECTP21 on the basal facet layer. 

The students dug on E and W aspects... around 9800'. On both aspects HS was around 110-120 cm, and both the midpack FC/crust and basal facet layers were less reactive. Between six snowpits we didn't have a single ECTP, and only a handful of CT results on either layer. 

All aspects were heavily wind affected."


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Northern Gallatin
NORTHERN GALLATIN RANGE
Snowmobile remote triggered 5' deep wind slab
Incident details include images
NORTHERN GALLATIN RANGE
HS-AMr-R2-D1.5-O
Coordinates: 45.4755, -110.9500
Caught: 0 ; Buried: 0

From IG message: "5' thick wind slab just behind little bear remote triggered riding along the ridge." @skidooin_it


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Bridger Range
Saddle Peak
Natural wide wind slab on Saddle Peak
Incident details include images
Saddle Peak
HS-N-R2-D2-U
Elevation: 9,000
Aspect: E
Coordinates: 45.7943, -110.9360
Caught: 0 ; Buried: 0

Avalanche crown(s) seen Wednesday (12/18), probably ran Monday or early Tuesday. Broke 200-300' across between the peaks and south central. Debris ran 1,500' vertical.  Photo: GNFAC

Additional info from a skier on 12/19/19: 

"Hard to tell how deep it was. Looked like 15” max maybe. Tapered off quick.  Looked like probably that south wind load. 

One crown was north between the peaks about 60 ft from the ridge top. Then it seemed to take the legs out of the stuff in South Central since the crown was 150 ft below ridge top. Then a little dribble made its way into Argentina bowl on the south aspect. Debris terminated right at the bottom of each chute. 

Since the crown was so low I never got eyes on it. Plus it has blown in a little. I stayed high near the ridge line to the pinnacles. But it looked and felt like a bomber crust is what it ran on. Hard slab with pretty small chunks in the debris. 

The one picture didn’t come out well but it looked like goat tracks went right into that higher north crown. Maybe a dead goat...  they are usually pretty smart though."


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Out of Advisory Area
Bison triggered Avalanche in YNP?
Incident details include images
SS-AW
Coordinates: 44.9268, -110.4510
Caught: 0 ; Buried: 0
From an email:
Upper Elk Creek, E. aspect, 8,200 ft
Debris looked pretty fresh, Who knows, but could have been triggered either directly or remotely by bison. The disturbance to lookers left (at bench) is due to bison - they are not cryptic animals!

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Northern Gallatin
Maid of the Mist
Shallow wind slab avalanches in Hyalite
Incident details include images
Maid of the Mist
SS-N
Aspect: E
Coordinates: 45.4164, -110.9700
Caught: 0 ; Buried: 0

1. From an email: The wind sure moved snow around up Hyalite last night, and our party observed several small to medium-sized releases that occured on a heavily-loaded east aspect overnight. None stepped down in the snowpack, but they certainly could have taken a person for a ride. Overalll, stability seemed to be good, with the exception of isolated wind-loaded areas.

2. From IG: Couple of small natural wind slabs around 10,200’ NE in Hyalite. Not sure exactly how recent. Played it conservative and chose to stay off a similar slope.


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Southern Madison
Taylor Fork
Large avalanches in Taylor Fork
Incident details include images
Taylor Fork
SS-N-R2-D2-O
Elevation: 9,200
Aspect: NE
Coordinates: 45.0607, -111.2720
Caught: 0 ; Buried: 0

Riders reported three recent avalanches that happened on or prior to 12/15. A couple looked natural, one had a lot of tracks nearby and may have been snowmobile triggered.


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Northern Madison
Buck Ridge
Slat Creek - 2nd Hand Report
Buck Ridge
U-AM
Coordinates: 45.1719, -111.3800
Caught: 0 ; Buried: 0

While teaching up at Second Yellowmule we received a secondhand report of riders in the Slat Creek area triggering 4 avalanches. It sounds like no one was caught, injured, or buried. 


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Cooke City
Republic Creek
Natural in Republic Creek
Incident details include images
Republic Creek
SS-N-R2-D2.5-O
Elevation: 9,800
Aspect: NE
Coordinates: 44.9855, -109.9410
Caught: 0 ; Buried: 0

From e-mail: "... This picture is from what I call the Sirens. Looks pretty recent. Steep terrain and repeat offender every season. We got some isolated collapses while skinning today. West face snowpit at 9600' revealed no issues with Thanksgiving later, but did get it to go 90cm deep on a Ect31, big wallop on basal facets."


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Northern Gallatin
Divide Peak
Small slide in Hyalite
Incident details include images
Divide Peak
SS-N-R1-D1-U
Coordinates: 45.4029, -110.9760
Caught: 0 ; Buried: 0

While on a tour in Hyalite yesterday, we were able to find stable snow on a south aspect at 9500 feet. Although we found no propagation in our ECT, we observed a defined crust layer about 2.5 feet down which was well bonded to snow above. On some steeper pitches near rocks bands, we observed top layer slough that moved naturally. We also observed a small crown from a day or two ago that broke between two buried rocks and only ran about 50 feet down slope.


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Cooke City
Crown Butte
Three snowmobile triggered avalanches near Cooke City
Incident details include images
Crown Butte
SS-AMu-R1-D2-O
Aspect: SE
Coordinates: 45.0525, -109.9620
Caught: 0 ; Buried: 0

From email: "Saw 3 different slides today, all had sled tracks near or into them, and were breaking from rocks... The other slides were smaller, had broken from rocks at the top of ridges. Also saw some cracking mid slope, on this same aspect, a ridge over down left of this photo."

Photo is of avalanche on SE aspect of Crown Butte.
 


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