Professional Observation
Basic Information
Observation Details
Observation Date:
January 11, 2020Submitted:
January 11, 2020Observer:
SAC - Martin StefanZone or Region:
Galena Summit and Eastern MtnsLocation:
Mushroom ridgeSigns of Unstable Snow
Recent Avalanches?
YesCracking?
IsolatedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
FairConfidence in Rating:
ModerateStability Trend:
WorseningBottom Line
The usual weak layers from early december and New Year's are present from mid elevation and up, but the lack of cohesive slab makes them unreactive. However, where the wind has done work the tune changes quickly. An ever so slight stiffening in the overlying slabs quickly brings back snappy results on the buried weak snow from New Years, now some 50cm down. Even if it looks better here than in other areas, it is still not an easy game to play.
Advanced Information
Weather Summary
Cloud Cover:
ObscuredTemperature:
teensWind:
LightLight winds at mid elevation, about 8" of new snow at 7000'. Light snowfall until early afternoon, accumulation not more than a couple of inches.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| Numerous | Past 24 hours |
Road cuts on Galena Pass SE 8600' |
D1 | SS | I-New/Old Interface | 20cm est | N-Natural | Most road cuts on the way up to the pass had avalanched, looked like soft slabs with just the new snow. |
|
Snowpack Observations
At mid elevation around 9000' both SW and SE non wind affected slopes HS around 110cm 12/7 (approx 60cm down) and 12/31 (approx 40cm down) are both present, and so is DH, mostly without crust. Test results were very indecisive, with a couple of high 20s ECTPs on DH and 12/31, but also ECTX on the same layers, and PST arr. Slab under 12/31 is faceted to various degrees, and not very cohesive. Storm snow on top also not very cohesive but shows subtle signs of creating a soft slab and gives up to 10 cm of propagation before arr on pst.
At 9500' on an ever so slightly wind stiffened slope (would still qualify as powder, but maybe a little more creamy than blower) HS 115cm 12/31 50cm down under 10cm windskin, 12/7 75cm down, snappy ECTP12 q1 on 12/31.
I did not venture any higher, but chances are that the wind has stiffened the slab enough both above and below 12/31 that it would become a concern.
Storm slab as such was not very responsive, but slides on the pass indicates that it might be elsewhere.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Persistent Slab
|
|
Layer Depth/Date: 50-65cm (12/7), 30-50cm (12/31), DH Distribution of this patchwork of weak layers is very widespread in the area, but reactivity varies from stubborn at mid elevations S 1/4 to reactive at higher elevs. Did not investigate other aspects today. |
Terrain Use
I avoided avalanche terrain except for short crossing of short runt out in low elevation sheltered terrain.
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