Professional Field Report
Basic Information
Observation Details
Observation Date:
February 2, 2020Submitted:
February 3, 2020Observer:
SAC - VandenBos (off duty), LinnetZone or Region:
Sawtooth and Western Smoky MtnsLocation:
Fishhook DrainageSigns of Unstable Snow
Recent Avalanches?
YesCracking?
IsolatedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
FairConfidence in Rating:
ModerateStability Trend:
SteadyBottom Line
New wind slabs and wind slabs from earlier in the week were primary hazard encountered. Fresh slabs were thin, soft, and isolated, but could be problematic with additional loading. Older slabs were stiff
Advanced Information
Weather Summary
Cloud Cover:
ObscuredTemperature:
Near freezing, cooling throughout daySnowing S-1 to S2 throughout the day with 6-8cm accumulation during tour for a total of 15+cm up high. Winds were moving snow in the morning hours, but not consistently - lots of sputtery, gusty blowing. Temps started out near freezing and cooled throughout the day, dropping into the upper teens F (estimated) by end of day up high.
Avalanche Observations
Lots of small, dry loose going on throughout the day. Fair amount of debris from wind event that occurred earlier in the week, probably 1/28 or 1/29, most of these piles were D1.5 or smaller in size.
Snowpack Observations
Ambient temp crust up to ~8,200' from warming event on Friday (1/31). Fresh snow was cold and low density (loosely stacked stellars) above ~7,500', a bit "stickier" below this. Freshly formed slabs were thin (<10cm) and isolated, but could become touchier with significant additional wind loading. Hard slabs from wind event earlier in the week (tough to set exact date, thanks to lack of upper elevation weather station in the Sawtooths, but probably Tuesday or Wednesday, 1/28-1/29) were unreactive and irregularly distributed. Hard to get a feel for what may have caused the avalanches observed 1/29 in Profile thanks to amount of wind affect. A similar depth crown, though considerably narrower, was observed today on N aspect at 8,900'. No direct observations on DH, but continue to find significant crowns from cycle before 1/15.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wind Slab
|
|
Comments: Thin, freshly forming wind slabs would have likely been reactive in the most favorable loading areas. Could be more of a problem with significant additional wind. |