Professional Observation
Basic Information
Observation Details
Observation Date:
March 7, 2021 - March 8, 2021Submitted:
March 9, 2021Observer:
WAC - Killian SumpZone or Region:
Southern WallowasLocation:
Upper Norway BasinSigns of Unstable Snow
Recent Avalanches?
YesCracking?
IsolatedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
FairConfidence in Rating:
HighStability Trend:
ImprovingBottom Line
Since the last major storm (3-4 ft of snow) on Feb 25, we've seen a warm-up, followed by a cool down, major settlement of the new snow, and a solar crust developed on E,S,W aspects. Over the weekend and Monday, 12 inches of light snow has fallen, and while it may not be a cohesive storm slab on most aspects, we have observed notable dry loose debris while riding steep slopes, and on Sunday, March 7th, a member of our party triggered a wind slab avalanche on a NE aspect near treeline. Only 2.5 inches of new snow had fallen at this point in time, we had light-moderate winds from the south throughout the day. No one was caught or injured. Keep in mind it doesn't take strong winds and lots of snow to form wind slabs - it was a good reminder for us, of how easily low density snow can be transported and loaded.
Media
Advanced Information
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Past 48 hours |
Norway Basin, School Bus Crash NE 7300 |
D1.5 | WS | I-New/Old Interface | 18 in |
AR-Snowboarder u-Unintentional |
Rider triggered slide near corniced feature, propagated hundreds of feet down the same wave-like feature. No one caught or injured. |
|
Crown: 18 in
Size: D1.5
Width: unknown hundreds of ft
Length: 50 ft
Snowpack Observations
Snowpack stability is good overall. We need to be mindful of the surface instabilities most importantly. Loose snow avalanches and storm/wind slabs are our key problems right now.
Terrain Use
This was our last run of the day on the mellowest slope angle of the day. We re-entered Norway Basin after having skied in another area all day. While playing on a corniced wind lip feature, a piece of micro-terrain we hadn't considered, the 50 ft tall wave-like slope couldnt help but release its freshly wind deposited load.
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