Upper Slate – West-facing terrain off Elkton Knob

CBAC CBAC Observations

Date of Observation: 02/25/2022
Name: Eric Murrow

Zone: Northwest Mountains
Route Description: Snowmobile out Slate River to just past Pittsburg. Ascended west and southwest terrain to Elkton Knob. Descended the same terrain.

Observed avalanche activity: Yes
Avalanches: In this terrain, there were numerous natural avalanche midstorm (partially filled bed surfaces) on west-facing below treeline terrain, generally D1.5 with one D2. We remotely triggered a steep west rollover from several hundred feet away.
Weather: Light snowfall and obscured skies in the AM gave way to mostly clear skies by 4pm. Overnight new snow accumulations around 2 inches. Westerly winds were transporting good amounts of snow above treeline and some near treeline.
Snowpack: Lots of loud collapsing on the February “drought layer” beneath the recent storm snow. Some collapses ran several hundred feet and shattered slopes less than 30 degrees. One collapse was able to connect to a small, steep rollover releasing a small avalanche 70cm deep. Westerly slopes tilted to the south had a thin melt/freeze crust capping the horrendous weak layer and northerly-tilted west slopes had the slab resting directly on the weak facets. Both structures behaved very similarly with long-running collapses. West-facing terrain below treeline is very much in the bullseye for human-triggered avalanches.

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