Sawtooth Avalanche Center

Pro Field Report

Basic Information

Observation Details

Observation Date:
January 15, 2020 - January 15, 2020
Submitted:
January 15, 2020
Observer:
SAC - O'Connor, Ahern
Zone or Region:
Galena Summit and Eastern Mtns
Location:
Mushroom Ridge - 7800 -9400

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced

Snow Stability

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

Bottom Line

deeper layers of concern now showing signs of strain with the recent load. similar tests in same location showed no propagation in prior obs few weeks ago, but now with results on ECT and PST tests.

without rest will consider wider margins and stepping back in route plans.

Advanced Information

Weather Summary

CLR to BKN. calm and cold to start the day, then S/ SW winds gusting to Mod by mid pm with signs of new snow transport (skin track filling, new windslabs)

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
1 Gladiator Pk
NW 9400
D1 SS I-New/Old Interface N-Natural None

Snowpack Observations

most prominent windslab development in areas exposed to NW winds. most prominent from 8800- 9400' (did not venture higher). 10-30cm thick (F+ --> 1F).

@9000', SE aspect, 30* HS 120

upper 70- 80 cm -- PP/DF. F-4F. no discernible LOC on CT or ECT
12/7 2mm FC @45cm LOC #1
oct snow? 3mm basal FC @15cm LOC #2

ECTP 29 on 3mm FC @15cm
PST 30/100 end @45 on 2mm buried FCsf
PST 40/100 end @15 on 3mm basal FC

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wind Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
Comments: although most prominent developement from NW winds, in alpine- more variable in distribution
Persistent Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5
Layer Depth/Date: 12/7
Comments: still here - now more reactive than in prior obs in this zone prior to storm cycle.

Terrain Use

closed obviously windloaded or windaffected terrain or slopes > low 30's. did not evaluate more wind pressed or wind slab affected terrain, but observed more significant results with recent load and I suspect these results would only be more pronounced where wind has enhanced cohesive nature of overlying slab