Pro Field Report
Basic Information
Observation Details
Observation Date:
January 2, 2021Submitted:
January 2, 2021Observer:
SAC - Chris LundyZone or Region:
Sawtooth and Western Smoky MtnsLocation:
Goat Creek (6400-8300', NE-E-SE)Signs of Unstable Snow
Recent Avalanches?
None ObservedCracking?
None ExperiencedCollapsing?
WidespreadSnow Stability
Stability Rating:
FairConfidence in Rating:
ModerateStability Trend:
WorseningBottom Line
At middle elevations, the weak facet layer sits beneath a dense 2+' slab. Due to the slab thickness, avalanches are becoming both more difficult to trigger and more dangerous if you do. The lower elevation snowpack is extremely weak, but generally lacks much of a slab except as you get closer to the middle elevations.
Media/Attachments
Advanced Information
Weather Summary
Cloud Cover:
OvercastNew/Recent Snowfall:
3-4cm of new snow since last nightVery light snow showers that increased to S1 for an hour or two around noon. Around 3pm, snowfall tapered off and some spots of blue sky appeared. I did not get high enough to assess wind.c
Snowpack Observations
Snowpack off the valley floor is very weak and lacks a slab. Seems similar to the pits I've seen around the WRV. The slab depth slowly increases in thickness and strength as you go up. Around ~7000-7500' collapsing was widespread due to the combination of a bit of a slab and a very weak snowpack. Skinning was difficult and trap-doorish. By 8000', the snowpack became more supportable and the collapsing stopped.
@8300', NE: HS 130cm. ECTP22, ECTN25 down 45cm on small, barely FC below the solstice crust. ECTN25, ECTX on 12/11 FC down 70cm. Base of slab was 1F, FC were 4F. The ECTP beneath the solstice crust was interesting.
@8200', ENE: HS 140cm. ECTP18 down 70cm on 12/11 FC. Snowpack structure here was very similar to the first pit, no obvious explanation for the different test result. But a propagating result on a weak layer beneath that thick and dense of a slab is always a heads up.
The 12/11 FC in both of these pits felt stronger (4F) and looked much less distinct than in other pits I've done. Hand pits on SE indicated a 60cm slab and 12/11 FC that were weaker (closer to F).
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Persistent Slab
|
|
Layer Depth/Date: 60-70cm Weak Layer(s): Dec 11, 2020 (FCsf) Comments: Colored in rose where problem was observed. Seemed more reactive as you wrapped more E and possibly SE. ECTP18. Got one ECTP results below solstice crust, that bears watching as we add more load. |
Terrain Use
I bailed on what I normally consider a reasonable route up a soft shoulder to gain a safe ridge, but felt like I had more terrain above me than I preferred as I approached the shoulder. As a result, I did not get as high as I had planned.