Natural Avalanches, Bridger Range

Bridger Range

From Marienthal Observation: "Drove up to Bridger at noon and saw a large avalanche on along the road north of the fire station. It was 75’ wide, 1-1.5’ deep and 25’ vertical. HS-N-R4-D1.5/2. It was on an east facing slope, south of the long slope that has cornices. The slope with cornices hadn’t slid at this point. On the way home at 3:30 the larger slope with cornices had slid. It was very big, possibly R5. 1.5-2’ deep, 200’ wide, huge chunks of hard slab and cornice. Looks like new wind-loaded snow with some gouges into older snow.

From Olson creek I had a cloud-free flat light view of the ridge from Saddle to Bridger Peak and looked with binoculars. There was a wind slab just north of quarter saddle that did not go over the cliffs. Probably 1-2’ deep, 30’ wide of new snow. There was a large wind slab on the north half of Between the Peaks (250’ wide) and one similar depth wind slab in the Pinnacles (100’ wide). Both of these broke 1-3’ deep immediately below the cornice and did not entrain much snow or propagate very wide or downslope given how much new snow there was. I could see the debris from the slide between the peaks which ran over 1000’ vertical to the top of the runout zone but relatively low volume."

Number of slides
Number caught
Number buried
Natural trigger
Snow Observation Source
Slab Thickness units
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year