Snow Observations List

From obs: "It slid 10' or so."

Hey Guys,

Brent and I got the public Avalanche Beacon Park installed today. It's located in the Old Airport area just off the Two Top trail, here in West Yellowstone. The 8 beacons are all buried. We could use some more snow to help cover them a little more, hopefully the next few days will provide that and we'll be off and rolling. 

Thanks guys,

Jim Norlander

Dug a pit at 8650ft on a SE facing slope just a few miles west of Cooke City. ECTP15. Failed and propagated on facets underneath the most recent storm snow about 20cm down, didn't feel like a wind slab but presumably was partially wind loaded from the winds the past few days. Pretty much the entire snowpack under this recent layer is facets separated by crusts, with varying levels of crystal thickness, ranging from larger near the ground to finer higher up. HS 65cm.

We rode into Yale Creek just south of Sawtell peak in the Centennials. Thin snowpack that is mostly faceted. There was a slight rain/mist the night before and again in the afternoon with warm air moving into the area ahead of the approaching storm. The rain/mist created a zipper crust on top of the snowpack.

The snow under that zipper crust is faceted and weak. It will be the primary weak layer once a slab forms on top.

Toured into Flanders today with the goal of skiing the E bowl/SE glades. Winds on the way in were nearly non existent at lower elevations. As we gained elevation, winds increased significantly, but the snow in the E bowl where we skied was largely unaffected aside from a very thin wind skin. Snow on adjacent ridges was clearly being blown. Some good jumps on a small wind loaded test roll yielded no results and a quick hand pit showed a slab that was fairly well bonded to the layers below. The hand pit slab fractured within the old snow on a layer of small facets. Some ski pole probing in many locations showed a relatively consistent snowpack in terms of hardness, but the lower snowpack is certainly of the faceted variety. 

Toured up to Midway meadows, observed no cracking or collapsing.  We found no propagation in our ECT at 8600' on a E aspect with HS 70cm. Found preserved buried surface hoar approximately 15-20cms below the snow surface.  Low tide in tree exit, but fun skiing!

Gusty winds transporting snow in Taylor Fork on Saturday. Triggered a 4-5 inch deep wind slab that propagated about 50 ft at the top of a north east facing slope at 9,500 ft.

We toured up Saddle Peak from Schlasman's today, for the first time this season, to get our bearings on how the snowpack in this area is shaping up. We skied down Skyline ridge from the summit and saw evidence of previous wind loading. Small cornices exist at the ridge crest and the snow surface off the ridge was rippled by wind. Though it has been several days since the last storm, strong winds have been present all week, and many wind slabs sit on weak snow. Thus, skiing down, we steered clear of wind slabs on steep slopes, especially with the high consequence terrain with large cliffs and trees below us.

We dug a snowpit on an E aspect at 9070'. We found a 1' thick hard slab sitting on a foundation of faceted snow. We got an ECTP13 on an interface between this slab and a melt-freeze crust. We dug another snowpit at 8800', again on an E aspect; here we found a deeper and stronger snowpack. 

Overall, we found quite variable snowpack depths and weak layer distribution. Currently, there is not widespread instability outside of recently developed wind slabs. Areas with a shallower snowpack (1-3 feet deep) had a consistent layer of faceted snow. Generally, these weak layers are not advanced, but we will continue to watch this snowpack setup once it is loaded with the weight of new snow.

We toured into Beehive Basin today and managed to get eyes on aspects throughout Beehive, Bear, and S Fork Spanish Creek Basins. We found excellent turns in spots, variable conditions in others, and a whole lot of rocks still exposed. Gorgeous, clear skies lent themselves to good visibility. Temps were cold at the trailhead but warmed quickly. Winds were predominantly from the South, gusting strong and moving snow around at ridgetops and summits. 

Winds seem have impacted upper elevations; low to mid elevations still held soft snow. Outside of true north-facing aspects, most other aspects have seen some wind effect and were in quite variable condition. In the hand pits I dug on several different aspects, I noted light snow atop either sun crusts or wind-blown layers, all with small but well-developed facets underneath. Gullies hold close to a meter of snow but generally, coverage seemed to be around half a meter in depth. 

Slab formation was limited to upper elevation ridgelines and little pockets in couloirs. Generally very few signs of instability were seen beyond one small (R1 D1) wind slab avalanche that came down from a rocky, exposed part of the ridgeline into Bear Basin. No surface hoar was noted anywhere. All in all, a lovely day to spend in the Spanish Peaks! 

We rode to the Taylor Fork weather station and along the edge of meadows in upper Sage creek. Two snowpits and video attached. Dug one in Sunlight Basin on ESE aspect (near weather station) and one in Sage Creek on NE aspect. ECTNs and ECTX test results.

While riding across Sage Basin we found surface hoar buried 4" deep in most handpits and in our snopwpit, and otherwise 1-2mm facets existed at the same depth.

Snow depth was fairly consistently 2 feet. Trail was thin, but soft and not too bumpy yet.

Wind was light to moderate with some strong gusts near the weather station. Very light snow was falling midday. Mostly cloudy with a few shots of blue sky.

I saw one small old wind slab on a heavily wind loaded short slope at the end of the trail.

Snow stability was good today, but the weak layers near the surface could change that quick depending on how much snow falls this weekend.

We observed snow being moved by wind out of the SW on the very top of lick creek meadow, as well as evidence of previous wind loading at the top of the NE facing side. We didn't get any whumphing or cracking in the spots we skied over.

We also noticed surface hoar in open areas in the approach and a sun crust on the SW facing slope.

Toured up Blackmore via the south ridge this morning. Winds overnight drifted snow over old tracks and skin  tracks around the area. Once on the ridge, I noticed active wind loading on eastern aspects as well as cornices growing along ridge lines. 

Checked out the snow above Mummy 2 and the Scepter. I was surprised how little snow there was, but a lot of it likely melted off during recent warm weather which was amplified by heating of all the surrounding rocks.

The old snow surface from last weekend is faceted but not too bad, and only has 6" of snow on top. The snowpack is generally very discontinuous. Climbers can mostly walk on rocky areas with minimal snow.

My main concern is what will happen when strong south winds arrive on Saturday. Some snow may fall Sunday and south winds may continue. Fresh wind slabs will be the main concern.

**This observation is not very relevant for the snowpack in the upper bowls of Hyalite where many ski**

Iv been fortunate enough to spend the past three days skiing around hyalite. On Monday, we were skiing a low angle gully a mile NE of Backmore along the ridge. We noticed new snow point and releases on most steep aspects above 40 degrees, no signs of new snow stuff stepping down. Today while on the East Fork ridge south of Palisades mountain, I covered SE-NW aspects and the new snow seemed well bonded. Solar aspects from the high pressure last week had an obvious crust layer, but new snow seemed bonded. On shadier aspects, I felt facets below new snow but no obvious signs of instability.. yet. 

Summited Mt. Blackmore 12/10. High wind and heavy wind loading were found, but minimal signs of instability were found within the wind-loaded areas. Some localized cracking and collapsing were observed throughout the boot pack but had minimal propagation. Before the climb, we performed an ECT on a wind loaded slope and found inconclusive results with ECTX. 

We skied near Lulu Pass and dug a pit on a northeast facing slope at 9,500'. There was 6-8" of low density new snow on top of a thick layer of surface hoar (10-16mm, photos attached). Snow depth was 90cm. There was a layer of small facets directly below the surface hoar, and below that the snowpack mostly had rounded grains and showed little signs of weakness. We had an ECTN12 on the surface hoar layer. While skiing I saw some 5 foot long cracks across the snow surface on a wind-affected convexity.

I'm not sure how widespread the buried surface hoar is, but this will be our primary interface of concern when we get more snow. We did not find surface hoar on south and west facing terrain in this area, but there was a crust with small facets below it buried 6" deep. Right now there is not quite enough recent new snow to create widespread instability. I do suspect a slab of drifted snow or a wind stiffened slab could propagate easily, especially if it lies on buried surface hoar.

Light snow fell most of the day with maybe an inch of accumulation all day. Wind was light and temps were single digits to low teens. Some moderate gusts in the afternoon, and winds increasing in town this evening. 

We rode out of the Buttermilk Trailhead to the old Ski Hill at Lionhead with Gallatin County SAR, Fremont County SAR, and local snowmobile guide from West Yellowstone for our annual West Yellowstone Avalanche Fundamentals class.

It snowed lightly all day without much accumulation (maybe an inch). Winds were stronger than I anticipated, but weren't moving much snow at 8000.' I suspect there was a bit more transport at higher elevations along the ridgeline, but there just isn't much soft snow available for transport. Isolated instability is tied to wind loading. At the Ski Hill breakover, we dug 40 people worth of snow pits. In a couple of them, there was just enough wind loading to get propagating results (ECT16-ECTP24) on basal weak layers. 

Recently, buried surface hoar and near surface facets didn't have enough new snow on it to cause problems, but it was preserved under 1-2" of snow. 

Skied from Beehive into Middle Basin today. On NE-E aspects there was ~25cm of low density snow over a supportive midpack. On SW-W aspects there was 5-15 cm low density snow over a supportive crust. Moderate NW winds were moving snow, but wind slab formation where we travelled was isolated to immediate ridgetop easterly aspects.

We toured up to Mt Blackmore today to assess how the snowpack is reacting to the recent snowfall. We traveled into the bowl and up the SE face to the ridge. Strong winds were noted off of ridgetops, as well as at lower elevations, before popping out into the bowl. But the SE face below the ridge was remarkably less wind effected than we expected.

The good news: Hyalite was the clear winner from our last storm cycle, and we noted around 15 inches of new snow at 9700'. The bad news: in our snowpit, we got an unstable test result of ECTP 13 on a crust - facet sandwich below the new snow. Unfortunately, the snow that makes up the base of our snowpack is made up of several old crusts and facets.

Where we traveled, we did not note much wind slab formation. Beyond our unstable test result, we did not note any other signs of instability - no recent avalanches or cracking/collapsing beneath our skis. 

Went north of Bridger Bowl towards Texas Meadows. 

Winds - blowing strong at the ridge and below about 7400 feet below most of the avalanche terrain (Top of the Alpine Lift down to the BB base area). Winds not doing much around the elevation of the Bridger Lift and the Ramp.

Snow - Just creamy, supportable skiing. South aspects have a supportable melt-freeze crust keeping you off the ground. North aspect have supportable snow. More wind affected areas had alternating scoured snow and wind-deposited snow, but skied pretty well. 

Avalanche issues - All tied to the wind. Fresh drifts were easy to find where the wind was blowing. Avoid wind effect and ski/ride soft snow and you avoid avalanches. The old snow surface faceted but not too badly compared to other areas. I suspect you could find areas where the old snow surface was more faceted and weaker, but they seem isolated.