Observation: Avalanche Professional
Basic Information
Observation Details
Observation Date:
February 23, 2023Submitted:
February 23, 2023Observer:
Avalanche Professional - Trevor KostanichZone or Region:
Snoqualmie PassLocation:
Alpental Valley/Denny Creek (3200-5200, All Aspects)Signs of Unstable Snow
Recent Avalanches?
YesCracking?
IsolatedCollapsing?
IsolatedMedia/Attachments
Advanced Information
Weather Summary
Cloud Cover:
Partly CloudyWind:
Moderate , SENew/Recent Snowfall:
Hn varied from 20-30cm. Over a crust below 4300'. Over dense settled storm snow above 4300'.Scattered clouds with periods of direct sunshine. Winds varied from calm to moderate with gusts transporting surface snow in open terrain and on ridgetops
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Photos | Details |
|---|---|---|---|---|---|---|---|---|---|
| 1 |
Feb 23, 2023 9:00 am () |
South side of Denny Mt SW 5290ft |
D1.5 R2 |
SS-Soft Slab | I-New/Old Interface | 0.5ft |
AS-Skier u-Unintentional |
|
Report |
Unintentionally triggered a soft slab at 9am while skinning into couloir feature. I was carried in slide, not injured.
D1-1.5, 5290', SSW
Crown: 40cm tapering to 10cm
Width: 10m
Length: estimate of 20m
Ran 200' vertical feet down slope
Additionally, easy to trigger dry loose avalanches that were running fast.
Snowpack Observations
Saw isolated wind depositions and while consistently checking with active tests, slope that avalanched went from no cohesion to 5cm of wind slab on surface to a triggered avalanche very fast (in about 20 vertical feet). Crust below new snow below 4300' made for difficult skinning conditions and fast bed surface for dry loose avalanches.
Avalanche Problems
Wind slab forecast seemed accurate. Lower density snow easily transported in many (some uncommon) areas.
Dry loose avalanches more likely on steeper terrain with bigger consequences in low elevation where running fast on crust.