Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Nate Hough-Snee, Manning, Richman
Observation Date:
December 21, 2022
Submitted:
December 21, 2022
Zone or Region:
East Central
Activity:
Skiing/Snowboarding
Location:
Icicle Creek

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Soft Slab
Size:
Size 2: Could bury, injure, or kill a person
Elevation:
3600
Aspect:
NE
Comments:
Plenty of weak snow failed during the 20 Dec storm: surface hoar, facets below a crust, and density changes mid-storm. Deepest crowns to 35cm

Signs of Unstable Snow

Did you see shooting cracks? 
Yes, Widespread
Did you experience collapsing or whumpfing? 
Yes, Isolated

Observations

Temps were 5F/6F at the car with OVC to CLR sky and high westerly winds shifting to calm, easterly flow. We saw plenty of recent storm slabs that had failed naturally mid-storm and also ski cut several D1.5 slides on rollover features above terrain traps. Crowns to 35cm, with snow breaking down to 12/8 in the deepest slides. Shallower slides were on facets below a crust, likely 12/18. A quick crown profile from a natural D1.5 storm slab found facets below the crust as the deepest layer of failure. Ski cuts triggered small slides that ran 50-60' in large concave features, with relatively well connected storm slabs on sub-ridges.

Media

Dry loose and storm slabs near Snow Creek TH
Example D1 intentionally skier triggered slide.
Example D1 intentionally skier triggered slide.
Cracking and sagging snow where storm snow failed on facets roughly 30cm down.
Example facets from within crown profile. 3600' E
D1.5 natural storm slab to 35cm deep, 50' long 90' long. crown profile shower surface hoar above a crust and facets below, breaking to the facets. 3600' E
D1.5 natural storm slab to 35cm deep crown profile. 3600' E

Advanced Observations

Observed Avalanche Problem #1: 
Wind Slab
Comments: 
Big collapse on a 125cm wind slab. 3800' E. Surface hoar below. Cross-loaded feature loaded from recent westerly winds. While worried mostly about storm snow over facets this one caught us by surprise breaking trail.
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