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.
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.
Mar 26, 2021
(+/- 1 day)
Lower slopes of the "Peanut" on the approach to the Pioneer Yurt
|D1||SS||AS-Skier||These appear to be two small, skier-triggered wind slab avalanches.|
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.
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.
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.