Pro Field Report
Basic Information
Observation Details
Observation Date:
February 16, 2020Submitted:
February 17, 2020Observer:
SAC - VandenBosZone or Region:
Sawtooth and Western Smoky MtnsLocation:
McDonald PeakSigns of Unstable Snow
Recent Avalanches?
YesCracking?
IsolatedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
FairConfidence in Rating:
ModerateStability Trend:
Advanced Information
Weather Summary
Variable cloud cover in the afternoon. Shreds of moisture were breaking free from the Sawtooth crest and pushing across the valley, producing periods of precip up to S2, followed by periods of sun. 10cm of new snow at the highway, closer to 15cm up high. Wind direction was pretty consistent out of the NW, but intensity was variable, with gusty moderate winds and then periods of relative calm. Temps slightly below freezing at the highway, estimated in the low 20s up high.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 5 |
|
D1 | L | S-New Snow | N-Natural | Small, dry loose sluffs initiating in the new snow and running on stiff surfaces underneath. | None | ||
| 1 |
N |
D1 | SS | S-New Snow | 15cm | N-Natural | Observed one small wind slab that released within the new snow on a cross-loaded terrain feature. | None |
Snowpack Observations
Went looking for distribution and behavior of fresh wind slabs. Inconsistent wind speeds made for spotty slab distribution, largely localized to close proximity of ridgelines, though did observe a bit of fresh slab formation in cross-loaded terrain a bit further downslope. Slabs that I encountered were not terribly touchy. Did encounter some cracking in fresh wind drifts in some areas, but this was only happening 5-8cm deep in very fresh drifts, and instability was confined to the new snow.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wind Slab
|
|
No direct observations on basal problem.