Snow Observations List

Me and my buddy went on a tour today up Sheep Creek to check out the new snowfall and conditions in the area. We dug a pit on a S\SE aspect at 9500 feet and found about 100cm snowpack. Last weeks snowfall fell right side up and was not able to find layers until the bottom 6 inches of the snowpack. About 6 inches from dirt, there is a minor crust layer with small facets under the crust. We did not find the new snow to be reactive to this layer during our column test...

Around 2ft down in the pit that was dug there is a generally stable storm slab but it still broke after 5 elbow strikes. Finger tip strikes did trigger a 3-4 in wind slab in the pit and a remotely triggered wind slab was observed halfway up the whiteworm. 40 wide and 5 in deep it ran for about 60 yd.

A skier remotely triggered an avalanche on Mt Blackmore (11/9/22).

From email: "I ski cut the top of the face and remote triggered a hard slab from 50’ above the crown. It broke full width of the couloir feature, 150’ wide and 10-18” deep. Broke on new snow/old snow interface which was another hard wind slab. The avalanche ran the length of the East face and stopped just below the last set of cliffs."

The pit depth was approx 80cm to the ground. Slope angle 19 Degrees. Air Temp 19* F. E/NE facing slope. Hardness Test/ Fist @ 64 cm, 4F @ 45 cm, 1F @ 35 cm, 4F @ 20 cm. Conducted CT (30cm x 30 cm column), Propagated at 25 (10 wrist, 10 elbow, 5 shoulder) propagation was just below the distinct layer that you can see at 35cm in the photo labeled BM5. Then conducted ECT (90 cm X 30cm) No propagation after 30 ( 10,10,10). Picture labeled BM4 is the layer that propagated on the column test.

Small slab avalanche triggered by skier in a small chute near The John and Bronco runs in Bridger Bowl. Propagation from skier’s ski, slab slid down through the chute. Crown maybe 10 feet wide. Slab looked about 6 or 7 inches thick. Looked like a layer of new snow from today and yesterday’s storm sliding on top of an old crust layer. Nobody harmed, just spooked. Watch out!

Our group of 3 skinned into beehive basin in search of fresh snow and expecting instability. We expected the bottom old snow to be likely decomposing and facted, as well as an interface between the wind affected snow and new storm snow. We dug a pit on an E facing slope 1/4 mile south of the lake, just past where the creek concavity eases. The slope we used for our pit was 23° and we found 80 cm of snow. See SNOWPILOT data for the complete snowpack. Our pit findings were drastically more positive than what we anticipated. The snowpack showed signs of being right-side up and having low slab formation within the new snow as well as weak layers that weren't very reactive. These findings provided us with more confidence in the early season snow than we had expected. As we moved south from our pit to a less wind sheltered area we found the upper 40 cm of the snowpack to be firmer than what was encountered from our pit. While ascending we used our poles to question this change and discuss how it would affect our planned objective. We still felt confident in our plan, but made note of a wind-skin on the surface to the south of us that we wanted to avoid. We got 4 laps on an East facing 35°-38° slope accompanied by 30 of our closest friends before skinning out with no instability observations on the slope we skied. There were however obvious point releases within and slightly buried under the new snow on adjacent west and southwest slopes further south down the basin. The west side appeared thinner with less coverage and more wind rippling as observed from afar. 

Today I got reassuring results from a snow pit dug at 9195' on a Northeast aspect (40 degrees) in the basin between Mt. Blackmore and Elephant Peak. The area was clearly wind-loaded with an HS of 110cm. I got a CT20, Q2 @ 50cm (see image), a resistant planar failure that appeared to occur on a thin layer of decomposing fragments. In my ECT, I received no results whatsoever, so I sense that this weak layer is quite unlikely to react, though structurally the snow consisted of a hard wind slab on top of an identifiable weak layer.

I also performed an analysis and multiple ECTs on a snow wall closer to Elephant Mountain (8950'), which was a Northwestern aspect (318 degrees). The snow wasn't as deep at this location (HS 73cm), and my results were ECTN22 @ 42cm, then ECTN21 @ 44cm (see images).

I hope these results are helpful as we begin to wrap our heads around this early season snowpack.

Thanks,

Charlie

Saw some cracking and propagation of a 6-8" storm slab on steeper terrain near the Bridger Lift. Gentle upslope winds seem to have compacted a slab near some terrain features, and I got a small propagation at the edge of the Sluice Box gully where the slope angle tipped up near 40. 

4:30 PM Sunday Nov 6, 2022.

I was skinning up Bradley Meadows. I was about 2 switchbacks from the top on the slightly steeper pitch. I pulled over to dig a snow pit and found a week later of facets appx 7" from the surface and a second week later just above the ground. I performed a compression test which failed on the second tap from shoulder height at the upper facet. 

I interpreted this as a questionable snowpack and returned via my low angle skin track.

During the annual setup for the Hellroaring Hut we underestimated the amount of snow based on snotel readings in the area. 18”+ in shaded areas around 7,500’ and < 6”-12” on solar aspects, steep solar aspects were already melting out and bare ground was being exposed. Thick sun crusts we’re already formed on most solar aspects, while shaded regions remained unconsolidated. Lots of surface hoar growth in the meadows. Long story short, it’s good to know the relationship/aspect of the Snotel sites you trust for data mid winter, going forward although wary season snowfall was limited there will likely be some interested surfaces to contend with in the Centennial Range until the snowpack gets deep enough to begin the healing process…

-Sam

While traveling up the Fairy Lake road, we observed the aftermath of an avalanche in October Bowl. The avalanche was D2-D3, start zone was at approximately 9000 ft, north east aspect, crown depth and width is unknown.

Went for a short walk in the Bridgers this afternoon (3-11-2022) for a few turns, and to get eyes on how the snowpack is shaping up. We headed from the base to the terrain above Alpine. In the apron of Hidden Gulley, two small dry loose sluffs were visible. Another dry loose sluff was present further north on the ridge. They all appeared to be natural. A photo has been attached. Deciding the apron was too thin for turns, myself and my partner opted to traverse to Bradley Meadow. 

On the way, we dug a quick pit at about 7500 feet on a shaded NE aspect (photo attached). Close to the ground, mixed forms were present with pretty clear faceting occurring. A stout sun crust capped the old snow. Atop the crust and beneath the new snow was a clear layer of large graupel particles, potentially setting the stage for a weak layer with high spatial variability down the road. Deepest snow depth recorded in a shaded area was approximately 50cm. 

Our primary hazard today was the rocks and stumps associated with early season conditions.

Winds blowing hard from the N/NE, 30-40 mph gusts. Graupel falling at start of storm and accumulating fast. Left car at 9am with zero accumulation and returned to 4 inches by 2pm (11/2/22). North facing aspects within the basin had little to no snow left over from the previous storm as slopes were heavily wind scoured. East facing aspects at higher elevations had the most substantial base. Wind loading was observed in large, isolated drifts on top of the Love Chutes and at the rim of Frazier Basin. Snowpack was about 2 feet deep in these drifts with little connection to slopes below.

Warmed up a lot today as we climbed Middle in Beehive. Some large rollerball development by the time we were coming out of going home chute.

BB skiing in the past few days. Pretty impressive single-storm coverage. Skied from the top of the nose down to the base on Wednesday. Spotted a few micro wind slabs that had peeled during the storm but nothing large.

There was a big release down the top center of the Apron yesterday morning. Seen from afar so not certain what initiated the slide. 

Tiny wind slab on a SW facing aspect at 9150 ft

Relevant Observations:

Recent large avalanche observed on drive up: HS-U-R1-D2-S (didn't remember the aspect/elevation exactly) 

Moderate W winds and blowing snow on drive back

Depth range of 70cm - 100cm observed

ECTN12 down 43cm (W aspect,  8960ft)

We toured up Bridger Bowl yesterday (10/24). We saw no signs of natural instability on our way up, but the wind was moving snow around with wind lips and cornices forming along road cuts (unreactive to ski penetration). On the upper mountain we found snow depths from 2-4.5 feet depending on aspect, with the higher end of those totals being in sheltered north facing areas. After evaluating several steep wind drifted test slopes, we saw no signs of instability in the drifts. As the day progressed, the snow was becoming sun effected in the upper to mid elevations on solar aspects creating heavier snow on top of lighter density snow. Over all, coverage was decent with minimal rock bashing. On our drive back to town we spotted at least 1 point release south of saddle on a solar aspect above a cliff band. 

An observer saw evidence of wind loading creating the conditions for avalanches in the Bridger Range on Sunday. Cracking is an indicator of instability. The observer noted that the relatively small drift he saw was "nothing consequential," but this shows that unstable drifts are forming. They will be more consequential where there is more snow and as the wind creates larger drifts.