Observation: USA Bowl

Observation Date
12/16/2015
Observer Name
Chris German
Region
Salt Lake » Big Cottonwood Canyon » USA Bowl
Location Name or Route
USA Bowl
Weather
Sky
Overcast
Wind Direction
Northwest
Wind Speed
Calm
Snow Characteristics
New Snow Depth
16"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments
The east side (west facing) of the USA bowl had a mix of new and windloaded snow between 14 and 18 inches in depth that was very low density and made for excellent skiing. While snow at the top was fantastic, serious instability lurked below.
Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
The snowpack seemed to consist of three major layers, from top to bottom: 1) roughly 16 inches of very low density new storm and windblown snow, 2) about 10 inches of dense (between 4 fingers and 1 finger), compact snow that sat atop a yellow snow band (see picture), under which 3) about 10 inches of large, granular faceted snow sitting at the snow/ground interface. Isolated columns released after 14 taps (10 wrist, 4 elbow). Surprisingly, extended columns released at the snow/ground interface after only 4 taps from the wrist, and propagated across the entire column. This extended column observation was repeated, with the same results, three times. Such easy release, extensive propagation, and at such a low angle (27 ­degrees) kept us on very conservative terrain. No cracking or evidence of natural slides were observed in the USA bowl area during our tour.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments
Extended column tests were failing with very little force at the snow/ground interface. As the new snowfall compacts and weight is added from upcoming storms, I'm guessing the faceted snow at the snow/ground interface will be increasingly reactive. See above for further comments.
Snow Profile
Aspect
West
Elevation
9,400'
Slope Angle
27°
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Coordinates