Snow Observations List

Snowed hard all day. Lots of new snow (18” in the past 24 hours at upper elevations at 4 pm). Found 4 ft deep fresh wind drifts near the summit of Sawtelle Peak while going to work on our weather station. 

Rode into Yale Creek and dug on a south facing slope at 8000 ft. HS was 133 cm. Found 2 mm facets 40 cm off the ground (similar to what we’ve been seeing in the Lionhead area). Interesting to note that on this lower elevation sunny slope there was a melt-freeze crust above the facets and percolation columns running down into the facets. ECTP25 on the facet layer. As we rode to the head of Yale Creek the new snow kept getting deeper until there was ~18” of new snow where we dug again at 9000 ft on a NE aspect. HS was 235. ECTP8 and ECTP9 within and at the bottom of the new snow. Lower snowpack looked pretty decent and there wasn't a dramatic faceted layer. Rounded facets in the bottom meter, but 1 Finger hardness and no results in the ECT. 

All this new snow and wind drifting makes for unstable conditions. More snow this weekend will make the avalanche conditions even more dangerous. Finding weak layers in the snowpack means that avalanches could break deeper, could be triggered from below, or could be triggered after multiple people have ridden the slope. 

We recommend avoiding steep terrain and the runout zones below steep slopes for now.

I dug a pit above Silken Falls in the gulley. I found a weak layer of facets breaking about 10" under a wind slab (ECTP15). We did not get any cracking, but the terrain is very serious and even a small slide could be deadly. We did not feel comfortable center punching up the gully. Given how much traffic the gullies are getting, I do not think it is widespread, but it's out there and could avalanche.

Wind and snow this weekend may make this layer more unstable, so it's important to be careful crossing exposed terrain. Either rope up or tun around if it is suspect.

Got in my first tour of the year on Mt Ellis today! I dug a pit on an E/NE aspect at about 7650', and found 90cm of snow. I could not get anything to pop in a shear test, and an extended column had no result. The snowpack very gradually gained density from fist to 1F in about as nice of a gradient as I could hope to see. There was a ~5cm layer of slightly less dense 1-1.5mm facets right at the ground, but they were surprisingly moist and packable. When I finished my ECT, I pried at the back of the column and the whole thing tipped over, taking some dirt with it. This is my singular data point for the year, but my assessment of this small area is that the snowpack is fairly weak, but unstressed where there isn't any wind loading. 

Small slide from the cliff bands at about 9500’, on a NE facing slope on Blackmore - looked like it broke pretty shallow sometime after the snow yesterday.

We toured and skied on the Throne today.  Ended up being a one and done as the snow depth there still isn't deep enough to cover hazards, we hit a lot of rocks.  This was our second attempt here, tried on Nov 17th and thought there would be enough snow by now but it seems strong winds have been stripping this area of snow as compared to Bridge Bowl for example.  Snow depth on the east aspects of the Throne was highly variable but most of the coverage was on the order of 12"-16" deep.  East aspects varied from breakable wind crust to some supportable snow/crust with F hardness wind affected snow on top.  The winds must have been pretty consistent, even the tree protected north facing lower elevations of the Throne were wind affected. The entire southern aspect of Naya Nuki also looked very wind stripped with large bare spot visible at mid elevation.  The upper elevation east facing aspects above the Throne were also very wind affected.  We dug a pit about 75' below the high point of the Throne and then skied the north facing gully back to the North Fork Brackett Creek drainage.  Included a map pic to show were the pit was located.

ECT Results

12/8/2022 11:50am

HS: 80cm (this area was wind loaded, 200' away in the gully the snow was 30-60cm deep)

Air temp: 20F  Sky Cover: Clear  Precip: NO  Wind: Calm

Elevation: 8300       Location: N 45deg 52.9547min  W 110deg 57.1631min

Heading: 330

Slope Angle: 30deg

0-25cm - 1F, some faceting at this interface

25-65 - 4F, faceting at a snow interface layer at 55cm (possibly a decomposing suncrust?)

65-80 - F, wind deposited snow, not much cohesion

ECTN 21 at the 55cm layer, very rough failure plane, no propagation

ECTX on the remainder of the column

Comments:  The area is so variably covered right now that this test was mostly for curiosity sake and gave us confidence to ski the north gully (lots of sharky rocks) and call it a day.

Two small natural avalanches observed today from the YC. Both on likely wind loaded easterly aspects on slopes around Cedar Mountain at roughly 8,000’. 

We rode to Daisy Pass to look at the avalanche that was triggered by a snowmobiler two days ago (12/6/22). It was on the slope east of the pass that people often climb up and out, steeper than the normal route out. It broke 2-3 feet deep and 250-300’ wide, R2-D2. At the crown it broke on a weak layer about 100cm above the ground, but it broke closer to the ground in many places lower on the slope where the snowpack was shallower and weaker. I would guess one of those areas is where it was triggered from.

Next, we rode around the back of Fisher Peak to Lulu and dug on the southwest slope below the weather station. Here it was shallow, 100cm. There were weak facets near the surface, but no slab on top of them, maybe due to the southerly winds scouring it. Could become unstable if loaded from the north or with a lot of new snow. Finally, we rode up to the shoulder of Scotch Bonnet and dug on far south Rastas. HS was 145cm, we had ECTP22 and ECPT27 on a thin layer of facets sandwiched between two crusts 55cm off the ground. Despite the hard force, these collapsed dramatically and re-iterated the possibility of triggering a large, high-consequence avalanche.

There is windloading along the ridge line but the snow is pretty unaffected on the face. 

I dug 2 pits at different locations:

Pit #1: ECT N21 N28 

Pit #2: ECTX 

Both pits were on E slopes around 7,800 ft.  Overall feeling good with the snowpack there. It does have a slightly upside down structure but couldn’t get anything to fail.  

From IG: “Avalanche spotted on Henderson bench today, appears to be cornice triggered yesterday or the day before. 2-5 feet deep, 600’ wide, ran 800 vertical.”

We rode from Sage Creek trailhead to the weather station. After we got everything installed, we headed to Sunlight Basin to dig. There was about 12-15 cm of new and wind drifted snow. On the walk to the pit location we noticed the snow was punchy. HS was 94 cm on the E aspect. We got an ECTP 13 on a layer of 2 mm facets 44 cm down from the surface. New and wind drifted snow put a substantial slab on top of this weak layer. After we dug our pit visibility improved, and we saw a R1-D1 across the bowl that looked recent. While sledding around the area we noticed faceted snow in the middle of the snowpack in multiple locations.

Skied in NE Yellowstone Park today near Cooke City. No avalanche activity to report (low vis). Localized collapsing. No cracking.

We dug on a SE aspect at 8500'.

HS: 102 cm

ECTP25 @ 37 cm above ground.

Frequent shooting cracks, collapses, and whoomphs on wind drifted snow just north of town on a south facing aspect at 8,100ft.

We skinned into the Divide Peak cirque to check out the conditions in Hyalite for the first time this season. On our tour we saw a couple of small R1-D1 slides that had broken within the new snow. At our first pit we saw HS at 124 cm with 10 cm of new snow. We had a ECTP 30 on facets 64 cm down from the surface. Next we dug on a SE aspect with a HS of 127 cm and 15 cm of new snow. We got an ECTN-3 within the new and old snow. More importantly, the wind was picking up throughout the day, and it was transporting snow. Our primary concern today was new snow, and in the next few days it will be wind drifted snow.

The snowpack is getting punchy and soft, especially around rocks. The faceting has been taking a bit of a toll even though the snowpack is - relative to many Decembers - kind of deep. 

It was very windy in the base aream, and there were strong southerly winds blowing all the way up past the top of Bridger. It looked like there was plenty of windloading in the usual areas for southerly winds (like that northerly-facing side of north bowl). Lots of plumes coming off the ridge, and Saddle looked like it was getting blasted pretty good. We are certainly thinking about a hardslab on top of facets in the future. 

Observed active windloading on the eastern side of Lick Creek today.

12-18 inch slab broke easily when ski cut and a small but very reactive cornice was rapidly building.

West facing slope of Woody Ridge in Republic Creek. ECTn 21 at 65cm with a 120cm snowpack (8,842ft). Observed sugary facets close to the ground that did not react in our tests. No shooting cracks, collapses, or obvious signs of instability.

Cut a wind slab from the top of the John around 2:30. 3-6” crown. 50-75’ wide. Ran down to the low grade below

Two skiers triggered an avalanche while ascending the Banana Couloir on Ross Peak on the morning of 12/5/22. The skiers were approximately 150 ft from the top of the couloir when the avalanche broke 20 ft above the upper skier. The slide broke in wind drifted snow 6 inches deep and approximately 30 ft wide, across most of the couloir. The lower skier was waiting in a "safe spot on the side" but was also caught by the slide. The slide ran ~600 vertical feet, pulling out a deeper pocket of snow (1.5-2 ft deep) midway down the path. Both skiers were fully submerged as they were carried, but ended up partially buried near the toe of the debris. One skier had snow packed into his mouth and underneath his eyelids. They returned to the trailhead under their own power. 

Found facets sitting beneath a crust 60cm from the ground. Observed collapse on this layer in our pits but no propagation. 

Small avalanche below Henderson Bench. SE aspect. Likley Snowmobile-trigger did not confirm. 70-90’wide, 1-3’ crown, ran 40’