Skier triggered wind slab on Emmons
Date of Observation: 02/06/2023
Name: Zach Guy
Zone: Southeast Mountains
Route Description: Mount Emmons to 11,800′ on SE, E, and NE aspects.
Observed avalanche activity: Yes
Avalanches: Unintentionally ski triggered a small wind slab, about 10″ thick. I was hunting for wind slabs below a leeward ridgeline with unproductive ski cuts, but further down the slope than expected, a small pocket popped while I was skiing. Some folks at the trailhead reported triggering shallow soft slabs in Elk Creek area as well.
Weather: Cold, partly cloudy, a few brief flurries, and light to moderate northwest winds lightly drifting snow on ridgelines.
Snowpack: About 3″ to 4″ of new snow had been redistributed by southwest winds near and above treeline, with a bit of drifting shifting to northwest today. HS ranged from 180 to 210 cm near treeline where I probed. Also checked out a wind protected, northeast facing path that avalanched to near the ground in January. There, the snowpack was unusually shallow (HS 60 to 80cm in a few handpits), but the persistent slab structure appeared to be lacking the slab (snowfall after the avy has subsequently faceted), the original basal weak layer, or both. The most recent slab-forming event (late Jan) was unreactive in stability tests and while skiing steep terrain up to 40 degrees.
Photos:
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A small, skier triggered wind slab on a leeward slope in Racoon Basin
Avalanche Report #1
Estimated avalanche date: 02/06/2023
Number of Avalanches: 1
Location
Location: Mount Emmons
Location Specific:
Start Zone Elevation: NTL: Near Tree Line
Aspect: NE
Characteristics
Trigger: Skier
Trigger modifier: Unintentional
Type: Soft Slab
Failure Plane: New/Old interface
Size
Relative Size: R1 very small
Destructive Size: D1- Relatively harmless to people
Avg. crown height (inches): 10
Avg. width (feet): 30
Avg. vertical run (feet): 50
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Racoon Basin
5972