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Observation: 10420

Observation Date
12/18/2020
Observer Name
Matt Asay
Region
Salt Lake » Big Cottonwood Canyon » 10420
Location Name or Route
10420
Red Flags
Red Flags
Wind Loading
Collapsing
Poor Snowpack Structure
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Same
Problem #1 Comments
The wind has created sizable drifts on the ridge approach to 10420. Somewhat common and not dangerous in that terrain, but those same drifts line Northeast Bowl and the snow within the bowl has been pushed around and is waiting for someone to test it. (Narrator: Someone should not, in fact, test it.) There's a steeper rollover in the bowl maybe ⅓ of the way down. We didn't venture into the bowl so I can't say for certain, but given the drifting I saw everywhere else, I'd imagine there's snow waiting to fall at that rollover.
Snow Profile
Aspect
Northeast
Elevation
10,400'
Comments
Decided today would be better spent alive than dead, so stuck to trees. Throughout the approach to the summit, as well as on subsequent laps climbing the ridge around Northeast Bowl, we heard the snow collapsing. Yesterday I heard the snow collapsing and decided to step on it. Today I was much wiser. Same data (the weak, faceted layer is garbage that isn't going away soon), different decision. Happier skiing.
If you know the 10420 terrain, it's easy to stay safe by sticking to the ridges and then dropping into trees (Promise Land, etc.), which is what we did. When the sun popped out on our fourth lap, it was tempting to think of how great that bowl would be...until I remembered the facets I'd been skiing for the past four weeks...and the collapsing snow I heard on the way up, coupled with drifted snow. So we skied Promise Land/trees, and they were fabulous (as shown).
PS Promise Land, thanks to the wind storm earlier this year, has more deadfall than normal, but is finally skiable without needing base repair after each lap. (Narrator: He has, in fact, replaced big sections of his bases twice this season from skiing Promise Land.)
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable