Pro Field Report
Basic Information
Observation Details
Observation Date:
January 25, 2023Submitted:
January 25, 2023Observer:
SAC - Davis, VandenBosZone or Region:
Soldier and Wood River Valley MtnsLocation:
Soldier Mtns - Peak 1 and 2 (All aspects, 5800-9500)Signs of Unstable Snow
Recent Avalanches?
YesCracking?
None ExperiencedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
GoodConfidence in Rating:
ModerateStability Trend:
ImprovingBottom Line
Weak layers in the upper 3' of the snowpack produced unstable snowpack test scores on sunny and shaded slopes. It wouldn't surprise me to hear of a triggered slide in >35-degree terrain where these layers exist.
Media/Attachments
Advanced Information
Weather Summary
Cloud Cover:
Partly CloudyTemperature:
10-30FWind:
Strong , NWThere was a fog layer in Fairfield and Bellevue that quickly dissipated up the valley in both locations. Mostly sunny skies in the Soldiers with some thin high and mid-level clouds that were occasionally thick enough to cast some shade. It looked cloudier toward the Smokys. Wind blew strong from the NW on Peak 2 but wasn't digging into middle elevation while we were there. There was no snow left to move via NW wind barring an extreme wind event.
Avalanche Observations
There were a handful of D1 wind slabs in the foothills N of Fairfield. They likely failed in the last 3-4 days. Slabs were confined to ridge caps but were up to a few hundred feet wide.
Snowpack Observations
Above 8,000', much of the snowpack is heavily shaped by the wind. We focused our efforts below this line and searched out a few spots that would give us a better baseline for the structure and average depth of upper pack weak layers in this area. We dug between 7,200-7,500' on two open planar slopes with slope angles around 24*.
(1/5) was down 35-45 cm. It was a non-descript crust + facet combo on a S aspect; ECTX x3. It was a 3-6 mm buried surface hoar layer (still upright) on an ENE aspect; ECTP 16, 24, and ECTN 15. The slab above was F to 4F+.
(12/19) was down 75-90 cm. It was a 2 mm facet layer under a crust on a S aspect; ECTP 26, 28, and 35 (extra shoulder hits). It was a 3-6 mm buried surface hoar layer (still upright with some 8 mm crystals) on an ENE aspect; ECTP 22, 26, and 24. The slab above graded from F at the surface to a significant portion of 1F and P+ near the base.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Persistent Slab
|
|
Layer Depth/Date: 75-90 cm Weak Layer(s): Dec 19, 2022 (FC) Comments: Shaded where observed. S = crust + facets, ENE = upright buried surface hoar. |
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|
Persistent Slab
|
|
Layer Depth/Date: 35-45 cm Weak Layer(s): Jan 5, 2023 (SH) Comments: Shaded where observed. S = ECTXs but the block failed when landing in the pit. ENE = upright buried surface hoar. |
Terrain Use
We didn't ski or ride in avalanche terrain. Each of these layers, considered separately, would have kept me out of large, steep, or consequential terrain.