Professional Observation
Basic Information
Observation Details
Observation Date:
January 13, 2020Submitted:
January 13, 2020Observer:
SAC - Martin StefanZone or Region:
Soldier and Wood River Valley MtnsLocation:
Triple PeakSigns of Unstable Snow
Recent Avalanches?
YesCracking?
IsolatedCollapsing?
IsolatedSnow Stability
Stability Rating:
FairConfidence in Rating:
ModerateStability Trend:
WorseningBottom Line
In this area the wind has done work drifting new snow into soft wind slabs that lie either directly on top of a thin and weak snowpack at low to mid elevations or on a combo of a hard windbuff under a few inches of soft, low density snow from 1/12 on higher elevation leeward slopes and ridgelines. This windslab is soft enough to be sensitive to a single skier, but stiff enough in places to propagate collapses and shooting cracks.
Advanced Information
Weather Summary
Cloud Cover:
Partly CloudyTemperature:
teensWind:
Light , SLight to moderate cold wind from south. The wind tonight has caused considerable wind transport, even in the valley and at low to mid elevations.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Past 24 hours |
Trail Creek N 6800' |
D1 | SS | I-New/Old Interface | N-Natural | Small slide probably triggered by cornice drop. Despite considerable wind loading this was the only activity I saw. |
|
Drove up to Galena Pass and back this morning. Glassing the boulders I could not see any activity, but visibility was less than ideal. No slides on the road cuts by 11AM. Plenty of wind transport from W over and through the pass.
Snowpack Observations
In this area snowpack comes in 3 varieties:
1: on solars, a lot of sage is still poking through. There are potential for some cross-loaded features to hold more snow, and fall in cat. 2.
2: Low and mid elevation shadies: 30-50cm of weak faceted snow with a fresh 30-40cm soft wind slab on top. This combo seems not to be very reactive yet, but more loading or wind could change that. There is an interface layer of FCsf in places, but without much of a bed surface I see it as a potential future problem and not an immediate concern.
3: High elevation and wind-exposed mid elevation shadies: Various kinds of wind buff, a thin layer of soft, low density storm snow from 1/10 with a denser 30-40cm F-4F wind slab on top, or a thinner but stiffer variation of the same. This combo is quite reactive giving shooting cracks up to 10m and lots of small to mid sized collapses. There is also potential for faceting in the 1/12 snow considering the density differences involved, might be something to keep in mind going forward.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wind Slab
|
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Layer Depth/Date: 1/13 |
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Wind Slab
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Layer Depth/Date: 1/13 Wind slab at low to mid elevs almost omnipresent, but not reactive to my tests, probably it's still too soft and the weak layer too thick (old snowpack) |
Note that these observations are only for the Lake Creek area, it is safe to assume that our old persistent weak layers have not disappeared where they have been present previously, but rather are straining under even more load than before.
Terrain Use
I avoided avalanche terrain.
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