Bridger Range

We triggered a small soft slab avalanche when skinning near the top of Pair Of Chutes in the Playground. The slab was about 1 foot thick, fist hardness, propagated 20 feet wide and ran 50 feet before breaking up and arresting. The slab did not entrain additional snow as it slid. The avalanche hit my feet but did not disturb my balance. However, it could have been dangerous above consequential terrain. Moderate gusting to high winds were sustained the entire day and wind slabs were widespread in the backcountry terrain north of Bridger.

We skied north from Texas Meadows to the Playground. Strong southerly winds were actively building wind slabs up to 25 cm deep in immediate lees at treeline. We experienced a few instances of cracking in this wind slab, propagating 2 or 3 meters from our ski tips. 

1 to 3 inches of new snow on top of a very hard base nearly every where with evidence of past wind affect. Condition were Sunny with calm winds and temperatures in the single digits. we saw no avalanche activity cause by snowmobilers or people actively skiing the Hollywood wall. Lots of people around.

Winds have worked over many slopes near the Throne. We found some slopes stripped nearly to dirt with the snow blown off to who knows where, and others had wind-sculpted sastrugi. Trees were broken off, and debris littered the snow surface. Photo: GNFAC

We rode to the motorized boundary and toured up the shoulder of the Throne, poked out to the north-facing runs at the top, and then moved to the south-aspect gully from the upper saddle. 

Winds have worked over many slopes near the Throne. We found some slopes stripped nearly to dirt with the snow blown off to who knows where, and others had wind-sculpted sastrugi. Trees were broken off, and debris littered the snow surface. We probed for snow depths. On the east face, depths ranged from 20 cm to 100 cm on the shoulder (we may have missed deeper spots). At the upper portion of the north-facing run, we found 50-75 cm depths. The south face had a 115 cm depth.

There was some isolated wind-loading mid-slope. We saw one old crown that was nearly drifted in on a steep break over at mid-elevation on the east face. 

Somehow, we found a slope sheltered from the wind's effects. Because the danger is low on non-wind-loaded slopes, we considered traveling down through avalanche terrain. Before we did, we assessed stability to give us one last chance to turn around, and we followed safe travel practices, exposing one skier at a time to potentially hazardous terrain.

Very reactive wind slabs developed overnight. 6-30inches thick. 

Wind loading on all aspects due to swirling winds. Cracking about 3-12” thick around top of wolverine forest. No signs of persistent slab instability, deep snowpack throughout.