Snow Observations List

Skied south of Cooke today and noticed a large natural avalanche just north of the South Siren. N-R2-D2.5-O. It wasn't fresh and likely ran during the last storm cycle. 

We dug on an east aspect at 9800', ECTX, HS150. No cr, co.

As my elevation increased, so did the wind. Heavy gusts were moving snow. Clouds were visible and moving fast above Bridger Bowl and Ross peak. Ross Pass was visibly wind scoured. 
 

I didn’t observe any natural avalanches in the steep terrain along the ridge between ski area northern boundary and Ross peak, but did notice some ski tracks (I believe in the “Trident, Dog Leg chute”). 

We rode into the Taylor Fork today to check out conditions after the new snow from the last two weeks. We traveled up to the weather station above Sunlight Basin, along Sage Basin to the the Beaver Slide, and through Carrot Basin to the wilderness boundary. 

No cracking or collapsing was noted today. We did note two small avalanches along the Carrot Basin headwall from sometime in the last two days that broke on weak snow near the ground. These areas looked to have a shallower snowpack. Besides old crowns previously reported, and these two slides, we did not see any new avalanches in the area. 

Near Sunlight Basin, we performed a snowpit test on an east aspect at 9480' (HS 98). It propagated (ECTP11) on weak, faceted snow near the ground. Our second pit, at the wilderness boundary, was on a south aspect at 8840' (HS 122). It propagated on weak snow below a melt-freeze crust near the ground (ECTP24). 

With blue skies, sunshine, and a lack of cracking and collapsing, it was easy to be lulled into a false sense of confidence about our snowpack. But with a loading event ending only yesterday and our unstable test results, we chose to reign in our enthusiasm, follow a conservative travel plan, and stick to riding lower-angle powder. 

Fresh snow had fallen the night of Jan 6th and through the morning on Jan 7th, about 4-6” of low density snow above 8000ft. No wind or recent drifting was observed. New snow from the past storm was 3-4ft deep, basically comprising the entire snowpack, the avalanche failed on a layer of depth hoar at the base of the snowpack.

As I made my way up toward emigrant peak I observed a very large natural avalanche that ripped out on a NE aspect at 9500ft. It propagated hundreds of feet wide and ran approximately 1500ft. The deepest part of the debris pile was ~15-20ft deep. The crown was approximately 3-5ft deep, maybe deeper. 

Observed several large collapses and whoomphing as I toured around the area. I observed at least 4 other natural avalanches in the area, not as big but still a tell tale sign to have cautious route finding and avoid slopes steeper than 30 degrees in this mountain range. 

Observed one avalanche in the steep chutes just outside the N Bridger Bowl boundary, SS-R2-D1-AS

HS between 150 and 200 cm. 90-120 cm of storm snow over firm mid Dec layers over facets. 15cm from the last few days. Some wind transport at mid elevations with lots of W wind up at ridgetop throughout the day. Much windier than expected in Bradley Meadow with moderate winds swirling from N and W. Sky was BKN and, no new snow. Temps around 10F.

Group from Wisconsin spotted 3 very fresh avalanches today. 2 for them near Red Canyon and 1 near Whites Peak. No other info. Might get photos tomorrow. 
 

2 other slightly older slides spotted

Skied north of Cooke today. The light wasn't great, but I think there is an older avalanche on the east face of Miller Ridge in steep terrain. Could barely make out a crown line near the ridge and old debris on the apron. Maybe it ran 3-5 days ago? No cr, co and the winds were light out of the W-NW, moderate at ridge tops. We picked up 8cm of low density new snow overnight, plus an additional 1cm throughout the day today. 

From IG Messages: “as expected, broke a slide out while ski cutting saddle today. Here’s the report. 

After summiting south saddle peak, we noticed wind loaded snow on top of an old avalanche crown (maybe 4-5 days old - 2’ deep). We made the decision to ski cut high, hoping to break out the new wind drifted snow. We were the first ones out there today with just a party of two still on north summit. No one below us. I was able to get several small pockets to pop before a larger pocket broke, triggering a sympathetic slab down lower in Argentina bowl. Both slides ran 1000-2000’ into the flats down low (crossing the standard traverse). Debris piled up 20’ deep and broke trees up to 6” in diameter. Slow start, but picked up lots of steam. We skied lower and found good snow below the ridge where there was less wind effect.”

Did a few laps on third meadow, and dug a pit. The pit resulted in two failures without propagation  pleasant skiing all the way down (new snow on top of old powder turns).

Pit Results

45.48054, -111.01267
~120cm depth

Facets forming on top in sun

ECTN5 failed 80cm above ground 

ECTN25 failed 30cm above ground

I went full barbarian on the column after 30 taps, and couldn’t get it to slide on the facets in the ground. 

Profile: Sugary facets 0-20cm; 1F 20-30cm; 1F crust @30cm, 4F 30-70. Fist 70-125cm (0cm is the ground). 

Very visible buried surface hoar layer was not producing ECT results so we cut a PST and got 30/100end. HS ranged from 105-135cm on leeward slopes and near 60cm on windward. 

While going for a walk up the main fork of hyalite today I spotted this crown below the upper cliffs on the maid of the mist 

Multiple large avalanches on different bowls and different aspects of Cedar. Photos taken from Yellowstone Club by YC Ski Patrol. NE and E aspects. Both approximately 9400 feet elevation. Shaded photo is N aspect, photo with sun and shade is NE.

Just wanted to send in a quick ob about snowfall.. in the last 24 hours at the Roost it snowed about 4 inches despite Fisher recording 0 inches of SWE

With decent visibility we drove up Bridger canyon to Battle Ridge to look for recent avalanches. The most noteworthy was a slab 500'+ wide, 2'+ deep in Argentina Bowl (photo), and there was an R1-R2 sized debris pile below the Saddle Peak cliffs, but clouds obscured the top of Saddle. There were a few short, small wind slabs that broke along the ridgeline north of Bridger Peak. We also saw a 150' wide storm slab in Truman Gulch (photo).

We looked at the snowpack on the west side of the range in Truman Gulch. In four snowpits HS was 70cm (W, 8200'), 112cm (SW, 8400'), 135cm (NW, 8000') and 140cm (W, 8500'). The two deepest pits had ECTP28 on facets (2mm) 40cm above the ground. The other two had poor structure and soft weak snow in the bottom 30-40cm, but did not propagate in tests. Overall, the snow structure is poor and not trustworthy on the west side of the Bridgers. With more loading we could see big avalanches, whether it's this week, later this month or later in the season, and currently it seems possible a person could trigger a persistent slab avalanche here.

On the ramp there was evidence of yesterday's wind in the form of wind slabs that broke and their debris subsequently drifted over. Today wind was calm to light, and there is plenty of snow to transport if the winds do pick up. A few hours of moderate wind could easily form fresh wind slabs. Snow was starting to fall lightly in the late afternoon.

Toured up Ellis today. Snow was starting to fall again in the late afternoon. HS varied from fairly thin below 7000 ft to about 110 cm at the top. We found supportable new snow and good skiing. Dug a hand pit at 7500 feet on a NE aspect and found about 50 cm of new snow sitting on facets over a melt freeze crust. At 8300 ft we did an ect on an E aspect and found a similar structure but had no results. 

Toured up into Blackmore basin this afternoon and skied the SE Shoulder. Moderate winds from the north were transporting some snow, but I was surprised by how calm it was up there. Small cornices had built up on the shoulder. S-1 snowfall beginning at 2pm and increasing as I skied out. The coverage is amazing - nearly tree skiable in the forest and HS on the shoulder around 9650' was 160cm. Top 100cm was F-1F hardness; bottom 60cm were weaker, faceted grains. I saw no cracking or collapsing. 

The one thing of note was a recent avalanche on the north face of Blackmore. Visibility was poor but it was a small pocket in a steep, rocky zone that broke near the ground. 

Big whumph as we stepped up onto the lower meadow to dig a practice pit. Pit was about 75cm deep, NE aspect, looking toward Trail Creek Road. CT12, 3cm from the ground, ECTP 16 on that same weak layer of facets just above the ground.

Toured up northwest of the bacon rind trailhead to the ridge. Did two pits, both with similar failures on the buried weak layer during ECT. Pleasant skiing in low angle terrain. Roller balls made an appearance down low @ 7400”. 

Pit 1

44.96190, -111.08941

95cm snow depth ECTN21. Failed on faceted snow that existed 23-35cm above the ground.

Pit 2

44.95982, -111.09903

100cm snow depth

ECTP17. Failed on faceted layer 30cm above the ground. 

sugary fist snow 20-30cm above the ground; somewhat consolidated 4F storm slab 30-60cm; powder fist snow 60-95cm

Skied above hebgen today, and conditions were similar to what they were a couple days ago. An east facing pit at 8700’ had 85 cm of snow and failed on facets near the ground at ECTP 16. I ski cut a steeper slope and got no result, but my larger-volume partner was able to trigger a slide that broke 40-50’ wide and ran to the ground and through some trees. This was immediately adjacent to the fresh tracks of a very fortuitous skier and their pooch. Subjectively, it seemed like the basal facets had a bit more moisture in them today, but they are not strong yet. 

Here are some observations from our tour in Specimen Creek this morning. 

Winds remained steady throughout the day and were blowing from the southern half of the compass. Many ridgelines had been scoured down to the grass from yesterday's winds. HS was around 100cm around 8k feet and significantly shallower at lower elevations. New snow totals from the past couple of days was around 20-30cm. We experienced a remarkable number of thunderous collapses throughout the day (I lost count), one of which triggered an avalanche into Specimen Creek while we were in the flats. See attached photo.

I'd give this area a few more good storms before the touring is worth it back there. Lots of tree-dodging!