Not your ordinary wind slabs

CBAC CBAC Observations

Date of Observation: 03/11/2022
Name: Zach Guy

Zone: Southeast Mountains
Route Description: Traveled on southerly aspects of Gothic Peak up to about 11,400 ft. Conditions worse than expected, bailed on our route plan and skied on NW, W, and SW aspects of Snodgrass instead.

Observed avalanche activity: Yes
Avalanches: On wind loaded southerly aspects, we found sensitive wind slabs that we could easily trigger remotely failing on the 3/8 crust. Even from locations without any drifting or slab formation, shooting cracks would connect to a drifted feature and release it. We remotely triggered about 5 small wind slabs on drifted rollovers below treeline on S or SE aspects. Near treeline, we remotely triggered a large wind slab in the “mini spoon” that propagated 400 vertical feet above our location and crossed the whole slope; crown was 10″ to 24″+ thick. There was also a large natural that came out of the Spoon yesterday or last night, crown filled in.
With decent visibility, we spotted a handful of D1 to D2 slab avalanches that failed recently, recorded in a separate ob. Most looked like wind slabs failing within the storm snow. One appeared to be a large persistent slab below Scarp Ridge.
Weather: Cold and windy. Large plumes of blowing snow off of the high peaks. Continuous drifting in valley floor. Mostly clear skies overhead, some hazy clouds lingering over the Ruby Range.
Snowpack: About 5″ of settled storm snow over the 3/8 crust on southerly aspects. This crust formed during the one day of sunny weather in the middle of last week’s storm cycle, and I suspect there is some radiation recrystallization associated with it, given its behavior.
On NW aspects below treeline on Snodgrass, we got numerous collapses on the sandbox layer about 2 feet down. Some collapses required stomping, some went while breaking trail. We were in tight trees and collapses didn’t radiate very far. In windsheltered southwest facing terrain, we found stable conditions.