Snow Observations List

GNFAC
Cooke City
Scotch Bonnet
Weak facets buried, and new snow
Snow Obs contain video

This afternoon (2/5/23), we rode over Daisy Pass in hopes of seeing the recent skier triggered slide on Fisher Mountain, but it had started snowing and visibility was too limited to see the crown or get to the slide. We rode around the back of Fisher to Lulu Pass and then up to the south shoulder of Scotch Bonnet to dig a pit. There was an old, large pile of debris at the bottom of one of the Rasta Chutes that I assume slid last weekend.

We dug a pit at 9,600' on a southwest facing slope. HS was 160cm. Below last weekend's snow (1 foot/30cm deep) was a 10 cm thick layer of soft facets (F+ hardness). We had an ECTN 21 and ECTP 21 on this layer. The recent skier triggered avalanche on Fisher probably broke on this layer, on a more wind-loaded slope. This layer will be a problem for a while, especially as it gets loaded by more new and wind-drifted snow.

Wind was moderate out of the southwest-west, and at 4pm there was 3" of low-density new snow.

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C. Pruden
Bridger Range
Pits at the top of Texas meadows

ECTPX in two pits at the top of Texas Meadows. No active wind loading. 

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B. Dallas
Northern Gallatin
Flanders Creek
Recent avalanche activity
Snow Obsdrvation includes images

We observed some crowns from recent slides just south of the Flanders Peak east glade while touring up Flanders today. The snow was wind affected and slabby especially towards the ridges. No other signs of instability observed. We opted to stay in the trees and minimize exposure on the ski descent.

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GNFAC
Northern Madison
Beehive Basin
Buried surface hoar in Beehive
Snow Obsdrvation includes images
Snow Obs contain video

We toured up the ridge between Going Home Chute and Tyler's (below prayer flags). We saw evidence of a large avalanche that broke during the avalanche warning last weekend in Going Home Chute, R3-D2.5 (see photos). It appeared to have run to the end of the runout zone and tipped over small trees. We dug a pit near the top of our ascent on a west aspect at 9,100'. HS was 160cm and we found surface hoar buried 55cm deep (105cm above ground). It did not propagate or easily break in our tests, but it was a clear stripe in the wall and may have contributed to the adjacent large avalanche last weekend.

We dug a second pit over the ridge in Middle Basin on an east aspect at 9,200'. HS was 175cm and buried surface hoar was 80 cm deep (95cm above ground). It did not break or propagate in standard ECT, but did propagate cleanly after 4-5 extra hard hits. Old faceted layers deeper in the snowpack were generally strong in both pits.

We also saw a crown of a large avalanche from earlier in the week on the west side of Beehive Basin, on an east facing slope around 8,800'. R3-D2, 2-3 feet deep, 150' wide.

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G. brogan
Northern Gallatin
Mt Ellis
Mt Ellis report

Skied Mt Ellis today. The burn was heavily wind loaded at the very top but softened significantly as you got lower on the slope. I got an ECTX in my pit, the snowpack seems to be adjusting well to the recent load in this area. There were still multiple layers of concern that would give me pause to step out into bigger terrain throughout the advisory area. 

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A. Alloway
Northern Madison
Deer Creek
Deer Creek Sat Feb 4th

Toured/ skied on S though E aspects between 6000' and 8200' and observed the following:

-No slab avalanches observed

-Several localized whumphs 

-Two hand shears that failed upon isolation down 35cm, sudden planar failure (storm snow/ old snow interface)

-Two hand shears that failed easy down 35cm, sudden planar (storm snow/ old snow interface)

-Stomped one freshly wind-loaded rollover on micro-terrain and released a small (15 cm - 30cm thick) windslab

Dug a quick pit on an E aspect at 8200' and observed the following:

-HS 120 cm

-ski penetration 22cm

-boot penetration 53cm

-CT 17 resistant planar down 35 cm (storm snow/ old snow interface)

-ECTP 14 down 35 cm (storm snow/ old snow interface)

Steady, moderate winds all day from SW and W; no blowing or drifting snow observed in our immediate vicinity

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Anonymous
Northern Madison
Buck Ridge
Snowmobiler triggered on Buck Ridge
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From FB message: I triggered this one Thursday night (2/2/23). Got lucky it didn't gain speed and sack on itself. Been in this zone 1000 times, never seen it slide, always gotta be on your game... NE aspect in Beaver Creek.

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E. Heiman
Northern Madison
Beehive Basin
Signs of Instability in Beehive Basin Area

Our group toured up into Beehive Basin yesterday with the goal of skiing Peru and returning via Middle Basin. Our ascents and descents on the day showed signs of small pockets of wind slab instability (cracking and small pockets pulling loose), but nothing significant. On our final ascent up the backside of middle peak, there was a large shooting crack, maybe 30 feet in length, but we adapted our ascent route and were able to avoid further significant instabilities. Hand pits showed a thin 2" wind slab on our final ascent slope. Throughout the day we noticed a few old crown lines varying from 1 to 2' in depth and up to about 150' wide. These crown lines were on E, NE, NW and W aspects. The debris appeared to not be recent as it was covered with new snow and eroded, and some of the crown lines were filling in. 

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BSSP
Northern Madison
Lone Mountain
Skier triggered slide in Lone Mountain backcountry

A 2’ storm snow avalanche in the Chippewa Notch area was apparently triggered by a rider. It propagated significantly across complex terrain, and ran through plenty of terrain traps/trauma trees.

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GNFAC
Northern Gallatin
Wheeler Mountain
Buried surface hoar in northern Gallatin
Snow Obsdrvation includes images
Snow Obs contain video

We looked at the snowpack at lower elevations in the northern Gallatin Range (SE aspect, 8,300' elev.) and found a layer of buried surface hoar below last week's snow that was reactive in stability tests (ECTP20, ECTP22). There was also weak, sugary snow through the bottom half of the snowpack that should be kept in mind, especially where the snowpack is relatively shallow. Triggered one small, isolated collapse on a west facing slope around 7,500' where the snowpack was mostly 1-2' deep weak facets, and we found one small pocket that had a drift over the weak snow. The buried surface hoar below last week's snow makes large avalanche possible to trigger for at least a few days.

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B. Sienkowski
Bridger Range
BRIDGER RANGE
West side avalanche photo
Snow Obsdrvation includes images

Impressive avalanche cycle in the Bridgers to view as the skies clear.  Most slides seemed to have happened mid storm.  Here’s some photos of a large slide on the west side/behind north boundary.  Not sure the name.

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K. M
Northern Madison
Buck Ridge
Avalanche near Buck Ridge wilderness boundary
Snow Obsdrvation includes images

Avalanche (possibly sled/human triggered) on an easy to northeast facing slope around 9300 feet.  There were lots of sled tracks on the slope, which is located just out of the wilderness at the far end of Buck Ridge.  Slide and sled tracks appeared to be from after the weekend storm and we're covered with light snow from the last couple days.  Noted lots of wind transported snow along buck ridge this afternoon.

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D. Halama
Northern Gallatin
Mt Blackmore
Whumpfing at Blackmore
Snow Obsdrvation includes images

Today we skied the northmost avalanche path on the east face of Blackmore; the farthest lookers right avi path before the trees. There were strong winds blowing from the southwest which created a very strong, 3-5in deep, wind crust. Certain aspects were heavily wind-loaded creating a very pocketed snowpack in some places. In the first 100 feet of my descent, I experienced three whumpfs; all of which came from different pockets of snow. Some areas appeared to be very well bonded, whereas others were far less so. We also observed multiple crowns across the eastern face, all of which appeared to have slid a few days ago. They ranged in width from 50-300ft and looked to be 1-3ft tall. The runout and debris were not visible. 

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Anonymous
Cooke City
COOKE CITY
Human Triggered Avalanche North of Daisy Pass
Snow Obsdrvation includes images

Dug at South facing snowpit at 9700' near the base of a wind-loaded slope, ECTX HS:280. Continued on less than 200' up the slope, the skier breaking trail triggered the avalanche. The third skier in the group of five was caught, carried, and buried to the waist. The crown was 1-2' deep, and 50 feet wide. Location: South of Fisher Mountain. Yesterday triggered a small windslab on a north-facing slope on miller ridge, no one was involved. 

 

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Anonymous
Cooke City
Mount Abundance
Small slide near Abundance
Snow Obsdrvation includes images

We triggered this very small slide on a steep convex  rollover by mt abundance. South facing. Triggered from on top by snow bike. Was only 60’ wide and didn’t run far at all. About a foot deep.  Some impressive high mark tracks in the area. No other signs of instability today.

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M. Standal
Southern Gallatin
Specimen Creek
Poor test scores and whumpfs in Specimen

Just wanted to report that I found very thin snow on west aspects in Specimen Creek, with unstable test results today.

Had an ECTP 13 down about 20 cm on the new/old snow layer from last weekend. Couple whoomphs, and observed some stiff WS formation on ridge lines. HS of 90cm and absolute junk on the bottom.

Great skiing on non-avalanche terrain, however.
 

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BSSP
Northern Madison
Lone Mountain
Skier triggered slide in Lone Mountain backcountry

Big Sky Ski Patrol reported a skier triggered avalanche in "The Mullet" in the backcountry outside the ski resort boundaries. One skiers was reportedly caught and carried by the slide. The initial skier triggered slide also triggered another avalanche in the adjacent "Rattail" avalanche path. Details are second hand and specifics could not be confirmed due to low visibility.

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GNFAC
Bridger Range
The Throne
The Throne - Fewer Signs of Instability
Snow Obs contain video

We skinned up the ridge of the Throne, and we dug two quick pits on the lower half of the slope. On the E aspect at 7,800' we had a HS of 4 feet. We got an ECTP 24 and 30 on the facets at the ground. 30 feet away, we dug a pit with less than 3 feet of snow, and we got an ECTX in that pit. This showed how spatially variable this area is after the new snow and wind. We continued skinning up the ridge to the top of the Throne, and we dug another pit. Here, we found 190 cm of snow, and we had an ECTP 14, 1.5' below the surface within the new snow from the last week. We did not see other signs of instability while touring or riding today. 

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T. Grande
Southern Madison
Bacon Rind
Snowslide creek area obs

Did a couple runs just to the north of bacon rind, had good runs. Dug a pit and did an ECT test at about 8300 ft on a SE aspect, snow pack was about 4 ft deep. I got an ECT-P10 with a Q2 shear quality. My column failed and propagated on a thin barely visible strip of surface hoar in between the new and old snow, there was about 12 inches of new snow. Also noticed ‘many thin (appeared to be 4-5 inches)slab crowns, on steeper terrain right off the rode near the pulloff West facing aspect, also tons of the same shallow looking crown on the spur road up to big sky on the steep south facing stuff above the road.
 

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M. Zia
Southern Madison
Bacon Rind
Poor structure in YNP

Skied near Bacon Rind Creek on 2/1/2023. Surprisingly little wind affect, still some snow on trees and a soft snow surface. Excellent low angle powder skiing in wind protected areas. Underlying snow structure very weak though. Weak layer likely from the December cold snap buried ~40-50cm from surface is super concerning, not to mention basal weak layers and new snow interface... New snow from the 1/27-1/28 storm has settled to a soft slab (F-4F) 35cm thick. Still lots of snow available for transport.

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