Pro Field Report
Basic Information
Observation Details
Observation Date:
December 30, 2021Submitted:
December 30, 2021Observer:
Chris LundyZone or Region:
Sawtooth and Western Smoky MtnsLocation:
Frenchmans Creek (8000-9000', SE-E-NE)Signs of Unstable Snow
Recent Avalanches?
YesCracking?
None ExperiencedCollapsing?
IsolatedSnow Stability
Stability Rating:
FairConfidence in Rating:
ModerateStability Trend:
SteadyBottom Line
The wind was transporting snow at upper elevations and loading lee slopes. I triggered a small wind slab on a wind-loaded ridgeline that broke 1-2' thick. The October snow is buried 4+' deep on shady aspects, making it difficult to trigger - but not impossible based on the reported large, rumbling collapse. Triggering an avalanche on this deeper layer will be more likely in upper elevation terrain that is steep, rocky, and wind loaded. I did not find any weak layers in the top 3 of the snowpack (snow since 12/22).
Media/Attachments
Advanced Information
Weather Summary
Cloud Cover:
ObscuredTemperature:
Single digits/low teens (est)Wind:
Moderate , WS-1 while I was out from 1100-1500, adding up to a trace. Light to moderate winds were swirling snow at mid-elevations but not doing any real loading.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 1 |
Wind loaded ridgeline E 9000 |
D1 | 30-60cm |
AS-Skier c-Intentional |
30' x 1-2' wind slab triggered by stomping and ski cutting on obviously loaded ridge. |
|
Snowpack Observations
HS ranged from 100-120cm on solars at 8100' to 190-200cm on NE at 8800'.
@8450, SE, 29*: HS 120-125. CT11 RP, ETN8 30cm down. Looked to be a midstorm interface, no signs of SH or FC with my scope. Just a hint of October snow on the ground, otherwise right side up and good-looking snowpack.
@8800, NE: HS 195-200. 12/11 down 135cm - found similar results by probing around on adjacent slopes. Bottom 70cm of slab is P. 12/11 is starting to "squash" and gain hardness, it was 1F-. No tests performed on 12/11. ECTX in the top 1m of snowpack and no visible layering.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wind Slab
|
|
Comments: Wind was moving snow and creating fresh drifts. I triggered a small wind slab. |
|||
Deep Persistent Slab
|
|
Layer Depth/Date: 130-140cm Weak Layer(s): Dec 11, 2021 (FC) Comments: Rose colored with presumed location. Riders reported large, rumbling collapse. |
Terrain Use
I avoided avalanche terrain where 12/11 existed. Traveled on small sections of solar terrain around 30 degrees.