Pro Field Report
Basic Information
Observation Details
Observation Date:
March 26, 2021Submitted:
March 26, 2021Observer:
SAC - Chris Lundy, Scott SavageZone or Region:
Galena Summit and Eastern MtnsLocation:
Hyndman Basin (6700-9600', snowpack obs primarily from SE-S-SW)Signs of Unstable Snow
Recent Avalanches?
YesCracking?
IsolatedCollapsing?
None ExperiencedSnow Stability
Stability Rating:
GoodConfidence in Rating:
HighStability Trend:
SteadyBottom Line
Yesterday's storm produced over a foot of low-density new snow at upper elevations in Hyndman Basin. This snow was blown into wind slabs that were sensitive but generally small. We observed natural and triggered wind slab avalanches. Cooler temps kept wet loose avalanches at bay, but you may have been able to trigger a small one on a steep, sunny slope.
Media/Attachments
Advanced Information
Weather Summary
Cloud Cover:
Partly CloudyTemperature:
Cool in shadeWind:
LightNew/Recent Snowfall:
~10cm at trailhead, 30cm+ above 9000' - low density (5-7%)Clouds decreased this morning leading to FEW or SCT clouds midday. Clouds increased again later in the afternoon. Temps remained cool to cold, although the late-March sun was warm. We didn't travel on any exposed ridges, but winds were light in exposed subalpine terrain.
Avalanche Observations
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Photos | Details |
|---|---|---|---|---|---|---|---|---|---|
| 1 |
Mar 26, 2021 (+/- 1 day) |
Gladiator W 10100ft |
D2 | SS-Soft Slab | N-Natural | Report |
| # | Date | Location | Size | Type | Bed Sfc | Depth | Trigger | Comments | Photo |
|---|---|---|---|---|---|---|---|---|---|
| 1 |
Lower slopes of the "Peanut" on the approach to the Pioneer Yurt SW 8800 |
D1 | SS | N-Natural |
|
||||
| 2 |
Galena Peak S ~10,400 |
D1 | SS | AS-Skier | These appear to be two small, skier-triggered wind slab avalanches. |
|
|||
| 1 |
Hyndman Basin S 9400 |
D1 | SS | I-New/Old Interface |
AS-Skier c-Intentional |
|
In addition to these slides, we observed several natural D1-1.5 wind slab avalanches in the Pios and in the Boulders near Galena Summit. Some of these ran mid-storm and were partially obscured. We triggered a very small wind slab on a test slope at 9400', S in Hyndman Basin - breaking about 25' wide and 1-1.5 feet deep.
Snowpack Observations
The new and recent snowfall has fallen on a variety of surfaces, including crusts, facets, and facet/crust combinations. On sheltered slopes there is no slab, but these layers may help explain the prevalence of wind slab avalanches. The sun warmed the top 5-7cm of the new snow on solar slopes, creating inverted, moist over low-density new snow conditions. This made for funky skiing and riding, and you it's likely you could have triggered a small wet (moist) loose snow avalanche in the right terrain.
Avalanche Problems
| Problem | Location | Distribution | Sensitivity | Size | Comments |
|---|---|---|---|---|---|
Wind Slab
|
|
Layer Depth/Date: 3/25, 30-45cm Comments: Based on natural activity and human-triggered activity. Would expect D2's to be uncommon, but the Gladiator slide shows it's possible. |
We didn't observe a wet loose problem, but as mentioned above, it may have been possible to trigger something in the right terrain.