Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Lane Aasen
Observation Date:
December 22, 2020
Submitted:
December 22, 2020
Zone or Region:
Snoqualmie Pass
Activity:
Skiing/Snowboarding
Location:
Alpental Valley

Triggered Avalanches

Did you trigger any avalanches? 
Yes
Was it intentional? 
No
Avalanche Type:
Soft Slab
Size:
Size 1: Relatively harmless to people
Elevation:
5200'
Aspect:
S
Comments:
Triggered a small wind slab when skinning up the couloir above the Thumbtack. Approximately 15ft wide and 1ft deep. Slid on a layer about 4" above the crust. I couldn't tell exactly what the weak layer was. My partner was about 10ft below but the slab was soft enough that it did not carry him.
Photo:

Signs of Unstable Snow

None reported

Observations

Headed up to Source Lake then towards Chair Peak. Planned on skiing the N slope of Chair but after triggering a small wind slab we turned around and skied low-angle terrain down to Snow Lake then exited via Source Lake.

Dug a pit above Source Lake at 4,250' on a SE aspect. 260cm HS. Found 30cm F snow on a 1cm rain crust with 4F wet snow beneath. The wet snow beneath the rain crust felt very soft and saturated, like it hasn't fully drained yet. Did an ECT and got no result.

Ski conditions were worse than expected considering that Snoqualmie got 6-12" of light snow last night. The snow was light enough that it was possible to hit the hard rain crust underneath in many areas. Strong winds last night made the snow surface extremely inconsistent with bare ice in some places and 2ft deep wind drifts in others.

Media

E Face of Chair Peak
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