Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Mike Rolfs
Observation Date:
December 15, 2022
Submitted:
December 16, 2022
Zone or Region:
East Central
Activity:
Skiing/Snowboarding
Location:
West of Mission Ridge

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Soft Slab
Size:
Size 1: Relatively harmless to people
Elevation:
6200
Aspect:
E
Comments:

Signs of Unstable Snow

Did you see shooting cracks? 
No
Did you experience collapsing or whumpfing? 
Yes, Isolated

Observations

I saw three avalanches, two on east aspects and one on a north slope. Two were in locations that have not avalanched in my experience. All three appeared to have been natural and to run on a wind stiffened layer (from the 12/8 wind event), not on the buried November 28 crust, but above that. The bed surfaces were clean white with a breakable crust. Some blown in snow and rounding of debris, crown and flanks suggest these did not occur today. I guess two days ago. The 12/8 wind crust is not visible in the pit picture below, but shovel shear and column compression both showed easy clean failure at this interface. I experienced one settling event in a 15m diameter topographical depression.

Media

East aspect soft slab avalanche #1. (Upper Marion Ridge) I've never seen this slide before.
North aspect avalanche #2 (Gnome tree) I've never seen this slide before.
East aspect avalanche #3 (old faithful) This slides all the time.
12/10 wind crust at ~75cm (not visible but reactive), 11/28 dirty crust at ~40cm, loose sugary snow bottom 15cm
11/28 dirty crust
telltale debris at 11/28 dirty crust
Crown at avalanche #1
Soft debris from avalanche #1 (could ski through it)
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