Observation: NWAC Observer

All Observations

Basic Information

Observation Date:

February 17, 2023

Submitted:

February 17, 2023

Observer:

NWAC Observer - Brooke Maushund

Zone or Region:

Stevens Pass

Location:

Lake Susan Jane Area (E-N-NW // 3800'-5400')

Recent Avalanches?

None Observed

Cracking?

None Experienced

Collapsing?

None Experienced

We found that with the upper end of hard force, we could get a failure on the same layer that the Shoulda Coulda Woulda slide ran on on 2/11.

Wind hovered between calm and light out of the NW in areas we travelled or could view. No wind transport observed at ridgeline.

Newly wind textured surfaces were not encountered in areas we travelled.

Advanced Information

Cloud Cover:

Overcast

Temperature:

<32°F

Wind:

Light , NW

New/Recent Snowfall:

HST=33cm / HN24=7cm

Sky was consistently OVC, with one or two very brief sun breaks in the afternoon. Snow was at S1 in the morning dropping to S-1 after 13:00. Winds were mostly calm in the BTL and NTL zones where we travelled, with light gusts out of the NW. We did not observe any wind transport ATL in terrain that we could see.

Avalanche Observation Comments:

3-4 old, D1 wet loose slides likely occurring during the warming event on 2/12 observed.

On a similar aspect and elevation to the slide that occurred on nearby Shoulda Coulda Woulda on 2/11, we found that with hard force the snowpack broke on same layer of weak snow above the MLK Crust(CT26 RP, down 91cm). While these rounding facets were on the smaller side (1cm layer of .75mm facets), they still produced a result. This means that while the snowpack is "healing", there are still weaknesses that in the right terrain — shallow spots with weak points, near rocks for example — could still be triggered to create a large slide, while unlikely.

We also got a break in the snowpack on the 2/12 crust (CT17 BRK, down 33cm) which can tell us that that new snow in the past few days is bonding moderately well to the old snow surface.

Problem	Location	Distribution	Sensitivity	Size	Comments
Persistent Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Weak Layer(s): Jan 15, 2023 (MFcr) Comments: Small facets exist above the MLK crust that are could create a slide surface for the upper snowpack. This layer is getting deeper and deeper into the snowpack, and getting hard to trigger, however it could still be possible to trigger in shallow spots with weak points, like in rocky terrain.
Wind Slab	N E S W	Isolated Specific Widespread	Unreactive Stubborn Reactive Touchy	D1 D1.5 D2 D2.5 D3 D3.5 D4 D4.5 D5	Comments: While we did not see any new wind slab formation given the inputs today, there was evidence of past wind loading mostly ATL, on leeward sides of ridges.

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