Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Hough-Snee, et al.
Observation Date:
March 16, 2022
Submitted:
March 17, 2022
Zone or Region:
East Central
Activity:
Skiing/Snowboarding
Location:
Icicle Creek

Triggered Avalanches

Did you trigger any avalanches? 
Yes
Was it intentional? 
Yes
Avalanche Type:
Wet Loose
Size:
Size 2: Could bury, injure, or kill a person
Elevation:
6500'
Aspect:
E
Comments:
Traveling on ridgelines and lower angle E/SE NTL terrain, we were able to generate substantial wet loose slides from cornice drops and slow skintrack cuts WL-ASc-R1-D2 and WL-ASc-R1-D1.5.

Signs of Unstable Snow

None reported

Observations

It's mid-March and the sun is getting strong. Solar aspects were melted out (debris paths aside) as high as 5000', creeks are open or opening, and cold smoke becomes hot pow as one crosses from true north to anything receiving sunlight. Pleasant post-storm travel and skiing can be found ATL and NTL, but not without the usual seasonal variety of surfaces and temperatures. On both NW and E aspects we found buried surface hoar 35-40cm down with a variety of crusts and weak snow layers beneath, demarcating recent storms and high pressure. The early-March crust is apparent, but did not jump out as much as the surface hoar forms that failed with CTs in the 11-13 range. While the slab is relatively small on top of these layers, we travelled as if we didn't trust them (because we didn't) and skied enjoyable, sun sheltered, lower-angle terrain .

Ski cuts on solar (E/SE) aspects at 6500' entrained wet grains into wet loose slides to D2, but failed to activate any slabs. This highlights the spatial variability of the new PWLs NTL.

Media

WL-ASc-R1-D2 - This slide began as a point release from a skinning cut of the slope and entrained wet storm snow E, 6500'
WL-ASc-R1-D1.5 - This slide began as a point release from a small cornice stomp above the slope and entrained wet storm snow E, 6500'
Pit tests found CT11 to CT 13, failing on small facets 30cm down and buried surface hoar 40cm down. The upper small grained facets were not as obvious in hardness profiles, but became apparent under load during tests.
Below the recent March storm snow lies a dagwood sandwich of crusts and weak grains. Right now the most reactive layer is the top stripe, which was a layer of fist/four finger- surface hoar.

Advanced Observations

Observed Avalanche Problem #1: 
Persistent Slab
Comments: 
We found multiple weak layers under the recent waves of storms, including buried surface hoar and small facets.
WordPress Lightbox