Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Nate Hough-Snee, Ethan Lockwood
Observation Date:
February 25, 2023
Submitted:
February 26, 2023
Zone or Region:
East Central
Activity:
Skiing/Snowboarding
Location:
Icicle Creek

Triggered Avalanches

Did you trigger any avalanches? 
Yes
Was it intentional? 
No
Avalanche Type:
Hard Slab
Size:
Size 1: Relatively harmless to people
Elevation:
4800'
Aspect:
NE
Comments:
On steep convex rolls we were able to trigger a few very small wind pockets: HS-ARc-R1-D1

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Dry Loose (Sluff)
Size:
Size 1: Relatively harmless to people
Elevation:
6000'
Aspect:
SE
Comments:
We saw solar cliff band wind features warm and drop small (to D1.5) loose wet avalanches that entrained dry snow.

Signs of Unstable Snow

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

Observations

We went up to 6800' for some pow skiing and to have a quick look at conditions ahead of the incoming storm. Dust on crust at 2500' gave way to wind loaded and wind scoured slopes, with some sheltered snow in between. Temps were mild and winds were light easterly BTL and light west or calm NTL. Moderate SW winds and moderate transport were visible above 7500'.

We had a quick dig at 5300' on N near a spot where I had accidentally triggered a large D2 wind slab avalanche in the past:

HS was 180cm; HST varied with wind exposure, but roughly 25-35cm excluding stripped aspects.
CT11 sudden planar @80cm (MLK crust-facet below; 2mm), cash registering out of the pit
CT11 sudden collapse @25cm on Valentine's Day crust-facets-crust (1mm)
CT27 sudden planar @80cm, also cash registering out of the pit
ECTP11 @25cm

The underlying structure appeared worse than the underfoot travel let on, although we had several collapses to 2-meter radius, and cracks to 2 meters in wind-loaded areas. Ski quality had wind skin characteristics above 4500', but was overall better than expected NTL. We stuck with our travel plan based on our field observations and didn't let mission creep set in.

Media

Representative shooting crack
Structure -  failures occurred @25cm (Valentine's Day; scraper) and 80cm (MLK Day)

Advanced Observations

Observed Avalanche Problem #1: 
Persistent Slab
Comments: 
We had a quick dig to compare with yesterday's southerly Johnny Creek observation and found CT11 and CT27 sudden planar shears (ejected the block) 80cm down on a crust-facet combo (MLK?).
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