Northern San Juan
AvalancheJeff Davis Ann Mellick · Mar 31, 2022 · Northern San Juan
Weather
The sky was clear in the morning, but clouds built during the day. Temperatures were mild and winds light besides the occasional gust.
Snowpack
The spring transition has begun and the snowpack varies greatly depending on aspect and elevation. On sunny slopes below treeline, the snowpack is cohesionless and wet below a ~20 cm surface crust. The crust is supportive to a rider on skis, but boot penetration was to ground. The frozen crust may break down with another round of warm temperatures expected this weekend. The snowpack on north facing slopes remains cold and dry, with a still-reactive persistent weak layer. Faceted snow buried in February sits below a 70-80 cm pencil hard slab. The last slab avalanche below treeline ran on March 11, but the Persistent Slab avalanche structure remains. The combination of the wet snow and lingering facets with propagating long column tests leaves quite a bit of uncertainty. So, while the weather is springlike, the snowpack remains in flux and is not yet in a reliable diurnal melt/freeze regime.
Avalanche
A group of skiers informed us as the trailhead they triggered a small Wind Slab avalanche on a southeast slope above treeline.