11-12

GNFAC Avalanche Advisory for Sat Mar 31, 2012

Snowpack and Avalanche Discussion

The southern Madison Range and Lionhead area near West Yellowstone:

Over the past twenty four hours nearly 1” of precipitation has fallen.  Below 8,000 feet this fell in the form of rain.  On low elevation slopes wet loose avalanches are the primary concern.  Wet loose avalanches typically start as point releases, but can entrain large volumes of snow in a short distance.  Terrain traps such as gullies and creek bottoms are especially dangerous in these types of conditions. 

An air blast produced a climax avalanche in the Pinnacles ski run yesterday morning (3/27). It ran just under 600’,  piled debris 15’ deep, and tore out several hundred feet of avalanche sign line and several 6” diameter trees. This run just gets a little more sun than the other ridge top runs. Photo: T. Leonard

Northern Madison, 2012-03-28

This wet slab avalanche was triggered by a ski patroller kicking a wet loose avalanche that stepped down to the ground.  The debris is still flowing in the photograph and will join the other debris from Slushman's gully. Photo: P. Carse

Bridger Range, 2012-03-28