January 9
Area:
Box Elder
Elevations, slope angles and aspects:
5200-10000’, angles to 40°+, west, north, east southeast and southwest
Avalanche activity:
There was a large slide from last Saturday's wind event in the north chutes. Both the chutes ran wall to wall.Crown varied in height from 6” to 8’. The eight foot crown was probably a cornice breaking off triggering the slide.
8' crown
Cornice chunks piled in the trees
The skier's left chute crown
Looking up the path from the bottom
The area of that portion was heavily wind loaded. That was in the skier’s left chute. The skier’s right chute was scoured almost to the ground. The crown in that location appeared to be 6”-12”. The left chute ran almost full track, 1500’+ vertical with a good sized debris pile. The slide took the majority of the snow running on faceted snow near the ground. It did step down from upper weaknesses in places. The right chute ran an unknown distance but now where near full track. The slide also broke out in the treed area between the chutes, so I’m thinking the total width was around 300’. There was activity on the east face and also the northeast face. These were new snow only, crowns blown in and running only part of the paths.
Also noticed a wet point release on Chipman shoulder southwest facing in the afternoon.
Slopes skied:
Portion of the skier’s right chute exiting onto the east face descending a thousand vertical or so. West facing from Deer Creek pass. West facing from the Northridge shoulder back down to Alpine.
Snow surface and conditions:
Several inches of recrystalized snow over a variable base out of the wind damaged. Sand boxing was common. Some sun crusted over facets were found on east and west facing Southerly aspects had a melting crust from daytime heating. The wind affected was boilerplate and satstrugi. I had to install ski crampons for the ascent of the north ridge. The upper elevation was wind scoured to the ground on both the northwest facing and the northeast facing, with scouring well down hill on the northwest facing.
Weather:
Bluebird with mild temperatures. A breath of west wind from time to time.
Snow pit:
Evaluation:
Much of the snow in exposed terrain is either scoured or has avalanched. That promotes stability until loaded, when bonding of old and new would be key. The wind sheltered has near surface faceting, at times extending down into the pack. Mid pack layering continues to support ski travel. There is faceted snow below the stronger mid pack layering. I would expect to see large avalanches if that receives a significant load, not currently forecast.
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