Pro Field Report
Basic Information
Observation Details
Observation Date:
January 4, 2023Submitted:
January 5, 2023Observer:
SAC - Davis, David, Lundy, Preuss, VandenBosZone or Region:
Banner SummitLocation:
Langer Pk (All aspects, 6,500-8,500')Signs of Unstable Snow
Recent Avalanches?
None ObservedCracking?
None ExperiencedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
GoodConfidence in Rating:
ModerateStability Trend:
ImprovingBottom Line
We did not observe any fresh avalanches or cracking and collapsing of the snowpack. We observed weak layers of snow in the upper 1-3 feet of the snowpack. These layers produced mixed snowpack test scores but indicate that triggering a persistent slab avalanche is possible, particularly in steeper, wind-affected terrain.
Media/Attachments
Advanced Information
Weather Summary
Cloud Cover:
OvercastWind:
Light , SENew/Recent Snowfall:
HST = 2 cm (overnight)Mostly clear skies on the drive north until Stanley. Low stratiform clouds clung to the Sawtooth Crest. A thicker bank of low clouds sat over most of the Banner Summit Zone. These clouds remained for most of the day, lifting and thinning later in the afternoon to provide diffuse sunshine and a breif window of direct sunshine at the end of the day.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 1 |
Pk 8922, Vanity Summit W 8700 |
D1 | SS | N-Natural | One older, small wind slab pocket was observed on Pk 8922 near Vanity Summit. | None |
Snowpack Observations
We set out to gather more information on upper-pack weak layers in the Banner Summit Zone. Snowpack tests produced mixed results; mostly ECTXs and ECTNs, and a few ECTPs (20-40 hits). Our most notable propagating results were ECTPs under the 12/26 crust and an ECTP on 12/19 surface hoar (details in images).
Surfaces (1/3): Light snowfall sometime on the evening of the 3rd or morning of the 4th buried a weak interface. On sunnier slopes it presented as a sun crust + small facets, on shaded slopes it was a thin humidity/fog/rime wafer capped with surface hoar. This weak layer was buried intact on all aspects sheltered from the wind and will likely be well preserved by additional snowfall today (1/5).
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Persistent Slab
|
|
Layer Depth/Date: 20-70 cm Weak Layer(s): Dec 19, 2022 (FC) Dec 8, 2022 (FCsf) Comments: Shaded where expected. Mixed results. See photos. |
|||
Deep Persistent Slab
|
|
Layer Depth/Date: 70-140 cm Weak Layer(s): Nov 27, 2022 (FC) Comments: Shaded where expected. This layer was welded to the ground on steep, low elevation southerly aspects. |
Terrain Use
We traveled on skis and snowmobiles through non-avalanche terrain.