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Wallowa Avalanche Center

Professional Observation

Basic Information

Observation Details

Observation Date:
January 29, 2021 - January 29, 2021
Submitted:
January 29, 2021
Observer:
WAC - Michael Hatch
Zone or Region:
Elkhorns
Location:
Angell Basin

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
Isolated
The upper snowpack structure is poor. We have 25cm new sitting on 5cm of facets on top of a rain crust = avalanche sandwich

Snow Stability

Stability Rating: 
Fair
Confidence in Rating: 
Moderate
Stability Trend: 
Worsening

Bottom Line

The Northern Elkhorns above 7,000' received about 25cm of new snow during the recent storm. This new snow is sitting on about 5cm of partially faceted decomposing precipitation particles, which rest on the slick rain crust from 1/12. Test results were inconclusive. Small column tests indicated sensitivity to initiation (CT-M's, SP), but large column tests (ECTN's) exhibited lack of propensity for propagation.

The new/old interface is problematic with poor structure. We did get some whoomphing on several low angle slopes we traversed. The inconclusive results could indicate the new snow hasn't yet stiffened enough to exhibit slab-like properties. There could be conditions out there where the new snow could be dense enough to be more reactive, especially where the new snow was transported and deposited as stiffer windslab with the recent strong winds. Another thing to consider is...time. As the new snow consolidates and gains strength over the next few days it could start to behave as a more cohesive slab capable of propagating fractures. Due to the uncertainty of reactivity confidence is low. Best remedy...keep slope angles low.

Advanced Information

File Attachment

AngellPit_1_29_21.pdf
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