Snow Observations List

Centennial Range
Sawtelle Peak
West of Sawtelle Peak
Incident details include images

Surface was boiler plate leaving Island Park. We rode up high to the ridge (9200’) to the west of Sawtelle Peak and dug on a NE facing slope, 9,200', 6' of snow on the ground. Weak, sugary snow is on the surface (near-surface facet) and the main issue with the new snow. The new snow won't stick to the old surface and avalanches will be likely. Sugary depth hoar facets are still felt in the bottom 40 cm but it’s stable for now. Snowpack is very similar to Lionhead. Danger is Low today, but when the new snow arrives through the weekend the avalanche danger will rise.  I imagine it will not bond on many slopes and it will not be obvious where the NSF will be buried.  Tomorrow will be vastly different than today.

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Centennial Range
Centennials - Idaho
Centennials: poor stability

I haven’t gotten a chance to write up my observations from the Centennial’s last Saturday but with this storm that’s occurring down there I thought it was important to reach out and let you know what I saw. The melt freeze crust from a few weeks ago and the rain crust from earlier in the season are still very present in the snow pack. There is about a 2 inch slab on top of the newest melt freeze crust that fractured on isolation. Should be a sporty couple days down in the centennials.

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Centennial Range
Centennials - Montana
Hellroaring

Observed 125 cm snow at 8200' on NE aspect. ECT showed propagation on each crust. South aspect at 7500' had ~65cm snow depth with similar crust but less reactivity. In general observed poor structure and poor strength everywhere.

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Centennial Range
CENTENNIAL RANGE
Tin Cup Pass-Mt. Jefferson-Centennials
Incident details include images

Snow above the rain crust is starting to become more of a cohesive slab. No recent avalanches were observed.

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Cooke City
Republic Creek
Republic Creek, Woody Ridge Zone 2

We did a short tour yesterday in the middle of the storm into the Republic Creek drainage. Skies were overcast with light to heavy snow falling at times. Winds were gusting at times 60-80 mph, enough to blow you over if you weren't careful. Variable snowpack, wet and heavy down low until about 8800 feet then it got colder and less dense but was blowing around all over the place. The new snow was setting up very slabby in places with cracking expanding outward from the skin track and storm snow easily sliding at every kick turn. We did not dig a pit and instead opted to bail out at about 9400 feet and ski tighter trees back down to the creek bottom and home. The winds had stripped snow on the windward side with some larger drifts on the leeward side. However, in the basin, winds were coming from every direction at times. Not a very scientific observation but wanted to share what it was like in the storm up there yesterday. Caution really needs to be practiced as there are dense storm slabs sitting on large surface hoar/facets that had setup from the days of high pressure and winds may have deposited large amounts of snow in places.

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Centennial Range
CENTENNIAL RANGE
Tin Cup Pass-Mt. Jefferson-Centennials
Incident details include images

Rain crust is still very present in the snowpack. Two natural slab avalanches on north aspect of Reas Peak, one from recent storm and one from previous storm. Photo is from a snowmobile triggered avalanche from 1/9/21, you can see the party and one of the members riding the adjacent slope. Snowpit attached as well.

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Centennial Range
Tin Cup Creek/Willow Creek Drainage

Yesterday I snowmobiled form the Keg Springs trailhead to Tin Cup Pass on Willow Creek. From the limited visibility we did not see any natural avalanche activity. We dug one pit on the Idaho side of the Centennials and found the total snow depth was 70cm and there were 2 distinct crusts in the snowpack and a fair amount of depth hoar. The pit profile was as follows:

70cm-55cm First Hardness
54cm-50cm 4 Finger
49cm-48cm Knife
47cm-25cm Fist (facets)
24cm-23cm Knife
22cm-0cm Fist (depth hoar)

Test Results: ECTN 12@49CM, ECTN 14@24CM

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Centennial Range
Centennials - Idaho
Island Park South West Aspect Tyler Creek Area
Incident details include images

Seemingly unsafe snowpack here in island park. A few very firm crust layers. One facet layer near the base which propagated. Two crust layers, both knife hardness, were stacked in each other with a small amount of facets between them. This layer went on CTE 8. I wasn't able to attach it but I will send it separately. We weren't in avalanche terrain today so there were no other observations.

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Centennial Range
CENTENNIAL RANGE
Near Sawtelle Peak
Incident details include images

Road cut south facing slope of 42 degrees, triggered intentionally by a guide, shows about 12 inches of windblown soft slab on top of a faceted layer (in this case more extreme due to aspect and inclination toward the sun) but was triggered only by chopping a hand into the snow a few times. This same faceted layer (the uppermost layer of a thick faceted layer of 1-2 fee) exists throughout the snowpack.

Also, the bottom-most layers of snow are very faceted and conditions have not occurred yet to set the snow for a base. Walking around your feet go right to the ground even in areas where snow is 2+ feet deep. There are many rock/tree hazards lurking under the soft snow because of this, two people in our group damaged their a-arms.

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Centennial Range
CENTENNIAL RANGE
Near Sawtelle Peak
Incident details include images

Lower elevation plateau with low snow accumulation due to consistent wind-scouring, consists of about a foot of faceted snow with a dense wind-blown slab on top.

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