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Observation: Park City Ridgeline

Observation Date
12/11/2021
Observer Name
Gagne/Duvernay
Region
Salt Lake » Park City Ridgeline
Location Name or Route
Park City Ridgeline
Weather
Sky
Overcast
Wind Direction
West
Wind Speed
Moderate
Weather Comments
Overcast skies with even a few flurries! Winds were moderate, but sustained, along the ridgeline.
Snow Characteristics
Snow Surface Conditions
Powder
Snow Characteristics Comments
Storm snow settling down to 30-40 cms (12-16") along Park City ridgeline.
Red Flags
Red Flags
Recent Avalanches
Cracking
Collapsing
Poor Snowpack Structure
Red Flags Comments
Tell-tale red flags when dealing with a persistent weak layer. On slopes with weak snow underneath the storm snow we were getting plenty of collapses and remotely triggered an avalanche as well.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments
Storm snow and recent wind drifts have put down an increasingly-dense slab on top of weak, faceted snow on northwest through east aspects at the mid and upper elevations. Now that we have a load on top of the weak facets, we have a much better idea of how widespread the weaknesses in the old snow are. The answer seems to be the facets in the old snow are widespread and quite weak!
Will list the trend as increasing danger with increased wind speeds forecasted beginning on Sunday.
Comments
Video describing poor snowpack structure along the Park City ridgeline.
Video
Photo and video of poor snowpack structure with full propagation of extended column test at 12 taps.
Video
With strong winds forecasted beginning Sunday, I am concerned these winds will drift the slopes facing northwest through east - the slopes that have the weak, faceted snow underneath recent storm snow. Storm snow and what appears to be a windy period ahead will likely continue to load these weak slopes. For now, anything steeper than 30° on the northern half of the compass are off limits.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable