Pro Field Report
Basic Information
Observation Details
Observation Date:
December 20, 2019Submitted:
December 20, 2019Observer:
SAC - LundyZone or Region:
Sawtooth and Western Smoky MtnsLocation:
Beaver Creek, 7000-9400', SE-E-NE-NSigns of Unstable Snow
Recent Avalanches?
None ObservedCracking?
None ExperiencedCollapsing?
IsolatedSnow Stability
Stability Rating:
FairConfidence in Rating:
HighStability Trend:
ImprovingBottom Line
We're getting into that dreaded period of the persistent slab life cycle...the stability is improving, but it's difficult to say by how much. Fewer signs of instability and improving test scores may lead to a false sense of security. The persistent slab problem is becoming more stubborn, but I'm quite certain there are still places you could trigger a slide.
Advanced Information
Weather Summary
Cloud Cover:
OvercastWind:
Moderate , SWIncreasing clouds through the day with a bit of a breeze along exposed ridges. Perhaps 1-2 inches of new snow.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 1 |
West of Pilgrim Mine NE 9200 |
D1.5 | SS | O-Old Snow | 40-50cm | N-Natural | Small mid-elevation slide | None | |
| 2 |
Head of Beaver Creek NE 9200 |
D2 | SS | O-Old Snow | N-Natural | Appeared to be two separate avalanches, likely ran at same time. |
|
The slides listed appeared to run on the 12/7 SH. Didn't have the best light, but couldn't see many crowns in upper elevation/alpine terrain. Suspect recent wind has been filling them in.
Snowpack Observations
A bit more total snow depth out here than in some other areas I've been. Depth ranged from 60cm at 8000', SE to 125cm on a 9300, N slope that had likely had some wind deposition.
The 12/7 SH existed everywhere I looked on aspects ranging from SE to E to N, generally 40-65cm deep. I only received two small collapses. I stomped around in a lot of sheltered and wind-affected terrain that was connected to slopes that were steep enough to slide, with no results. Some sledders were nibbling into the bottoms of some steeper slopes, also with no results.
8600', E, 15*:
Sheltered location. Total depth 73cm. 12/7 SH was 55cm down. Slab was 1F above weak layer. ECTN22, PST 50/100end, CPST 50/100end.
9300, N, 25*:
This slope had likely received some previous wind deposition. Total depth 125cm. 12/7 SH 65cm down, with 1F slab. ECTP30, CPST32/100end. Both tests slid into pit. See cartoon profile.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Persistent Slab
|
|
Layer Depth/Date: 40-60cm - 12/7 Comments: Observations point to decreasing sensitivity, but...it's a widespread buried SH layer. |
Saw a bit of fresh wind loading but nothing seemed reactive.
Terrain Use
Avoided avalanche terrain of any consequence.