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Observation Date
12/12/2012
Observer Name
Bruce Tremper and Trent Meisenheimer
Region
Salt Lake
Location Name or Route
Solitude and along the Park City ridge line to McDonolds Draw
Weather
Sky
Overcast
Wind Direction
West
Wind Speed
Strong
Snow Characteristics
Snow Surface Conditions
Wind Crust
Snow Characteristics Comments
The very strong south and west winds these past few days have done some major damage to the snowpack at all elevations, especially the upper elevation wind exposed terrain. It's a lurch-and-jerk affair and wide vehicles are better than narrow ones. You can still find some decent, dry, dense, old snow on wind sheltered slopes but you have to look for it.
Red Flags
Red Flags
Recent Avalanches
Wind Loading
Poor Snowpack Structure
Red Flags Comments
The main problems are the slope where there is a combination between the buried faceted snow from November and the recent wind slabs. You find them mostly along the north through east facing slopes in the upper elevation, wind exposed areas. It may be worse at mid elevations between about 9,000 - 10,000' instead of above 10k.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #1 Comments
There is no lack of wind slabs. Most are a couple days old so they don't collapse and crack as much as when they were fresh but when there is faceted snow underneath, they will be stubborn sleepers, where they will let you get out onto the middle of the slab before they break. I don't like them. I will continue to avoid all steep slopes with wind drifts that face north through east.
Avalanche Problem #2
Problem
New Snow
Trend
Decreasing Danger
Problem #2 Comments
Where wind slabs were deposited on top of faceted snow left over from November, they still have to potential to break out large and wide such as the McDonolds Draw avalanche and others recently. Persistent weak layers cause lingering problems, which make them so dangerous. These are wind slabs with an ATTITUDE. Again, avoid steep slopes that generally face north through east with both old and new wind slabs.
Comments
Here is a video by Trent Meisenheimer and me on the investigation of the McDonolds Draw avalanche that shows the basic setup.
Video