Quick report
- Slope Angle
- 39°
Avalanche
- Slab Width
- 53 m
- Weak Layer
- Facets
- Trigger Type
- Natural
- Avalanche Type
- Hard Slab
- Slab Thickness
- 91 cm
- Trigger Detail
- Cornice Triggered
- Start Zone Aspect
- Northeast
- Avalanche Problem
- Persistent Weak Layer
- Start Zone Elevation
- 3078 m
This natural, cornice-triggered D2 avalanche occured at the Barushka Bowl ridgeline sometime early morning and is an excellent indicator for the problems that exist in exposed, upper American Fork terrain.
To be specific, the video focuses on the larger part of the crown that was very fresh and the more eastern portion (looker's left) had a light wind-deposit on the bed surface, likely happened overnight. The two crowns connected mid-slope.
The crown ranges from 4-8' tall, ~175' wide with both sections and debris ran ~400' vertical to the runout zone. Flanks generally between 2' and 4' tall.
The failure layer here was Nov./Dec. facets, the same layer as the majority of bigger slab avalanches outside of the upper Cottonwoods. Sections of the crown showed step-downs from the Jan. 21 NSF layer but the slide ran on mature, striated 3-4mm facets (Pic 3). The strong winds have textured, sastrugi-ed, and welded snow on windward slopes but the NE and E in this area have been heavily wind loaded and the cornices on the ridge are likely to continue acting as triggers for the incredibly weak persistent layer. The structure here is not to be trusted until something substantial changes.
This is the Outhouse slide that was an accident/close call involving a Snowmobile group on Saturday. The right piece looks like it was sympathetic to the main slide in the conifer trees. There is still a lot of terrain like this that has not slid in popular sledding areas...