Professional Observation
Basic Information
Observation Details
Observation Date:
February 16, 2021 - February 18, 2021Submitted:
February 18, 2021Observer:
WAC - Killian Sump, Towner MenefeeZone or Region:
Southern WallowasLocation:
Norway BasinSigns of Unstable Snow
Recent Avalanches?
YesCracking?
None ExperiencedCollapsing?
IsolatedSnow Stability
Stability Rating:
PoorConfidence in Rating:
HighStability Trend:
WorseningBottom Line
At 7,000 ft in the Southern Wallowas we have a current snowpack height of 310 cm, just over 10 feet. Since last Friday, we have received pulses of snow everyday that have added up to to 90 cm or 3 ft. Underneath this new load of relatively light snow, there is an old melt freeze crust from last week's snow surface on most South and West aspects. During our tour on Wednesday, we heard multiple whumphs and remotely triggered a 3 ft deep soft slab on a W aspect (R1D1) that entrained a relatively small amount of snow. We saw 2 natural wind slab releases in the alpine that were D2 in size, entraining quite a bit more snow. Stability on N aspects near treeline was good. It is currently snowing heavy now, and 6-10 inches of new is forecasted for tonight.
Media
Advanced Information
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Past 24 hours |
Bob's Bowl W 7,100 |
D1 | SS | I-New/Old Interface | 3 ft |
AS-Skier r-Remote |
Skied a mellow run on a SW but placed the first turn on the top of the W aspect, causing a 50 ft wide crown to release 200 m lower down on the slope. |
|
| 1 | Past 24 hours |
Middle Fork Pine SE 6,800 ft |
D2 | SS | S-New Snow | 2 ft | N-Natural |
|
Avalanches observed make our main problems problems evident: storm slab and wind slab; as well as loose snow avalanche triggers.
Snowpack Observations
We dug a pit on a West aspect at 7,000 ft. No results on our Extended Column Test until banging hard on the bed surface 90 cm down. At that point it did propagate. During a PST, our 90 cm column failed at 95/100. Ski boot pen was waist deep, and a skier's stress bubble can go farther down into the snowpack during these conditions.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Storm Slab
|
|
Layer Depth/Date: 02-12-2021 / 90 cm |
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Wind Slab
|
|
Layer Depth/Date: 2-4 ft |
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Dry Loose
|
|
Terrain Use
We kept to lower angle slopes on solar aspects and skied steeper slopes on N aspects where better bonding between new/old interface had occurred. We did not venture above treeline.
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