Northwest Avalanche Center - Public Observation

Name:

Colin Wiseman

Observation Date:

December 28, 2020

Submitted:

December 28, 2020

Zone or Region:

West North

Activity:

Skiing/Snowboarding

Location:

Shuksan Arm/Mt Baker

Did you observe any avalanches?

Yes

Comments:

The wind slab, by my best guess, was roughly 80-100 feet wide, 1-2 feet deep, on a NNE aspect, and ran fast. Five riders had already descended the ridgeline rider's left on a slightly more northerly aspect. The sixth person entered further rider's right, aired in, and triggered the slab in a broad depression, which propagated to the tracks in the more featured terrain to his left. He was briefly caught before self arresting on a tree 100 yards downslope. The avalanche triggered another slide another hundred yards or so below and it ran to the valley without catching the others. It happened around 9:30 am in one of the few sunny spots on the slope.

Photo:

None reported

Although the NWAC forecast was "moderate" they did note tension in the snowpack, wind loading from the SW after two feet of snowfall, and a slick bed surface. Yesterday saw a remote trigger of a similar sized avalanche on an isolated terrain feature. My own observations from the past few days, including shooting cracks and snow that felt a bit "hollow," aligned with these concerns.