Gunnison

Avalanche

Ben Pritchett and Eric Murrow · Mar 4, 2020 · Gunnison

Weather

Hot day after a bitter cold start. Perfect melt freeze cycle. 50 degree F change from negative 10 to 40 between 7am and noon.

Snowpack

Persistent Slab avalanche structure exists on this slope below treeline with a 125cm total snowpack depth. The avalanche failed on a layer of facets below a thin crust 50-60 cm down from the snow surface. The slab is quite weak (4-finger to Fist hard) and includes the snow from the last two storms. Boot penetration to ground where HS <130cm. Nearby slopes with a bit more HS were supportive to boots.

Avalanche

This avalanche was triggered by a skier on a steep (37-40 degree) slope on 3/3/2020. The avalanche broke 50-60 cm deep on a layer of faceted snow below a thin crust. The avalanche measured about 250 feet wide, running around 200 vertical feet. The debris hit the lake with enough force to break the ice, creating a wet one to two foot deep sunken area in the ice and snowpack surrounding the debris. Cracks extended across the lake to the opposite shore of the lake. The debris ranged from three to ten feet deep. It appeared the skier was partially buried. Unfrozen lake water filled the hole where the person came to rest and skied out from the debris. A single ski track exited the debris pile and continued back to the nearby trailhead.