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Observation Date
4/24/2020
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon
Location Name or Route
Upper BCC and LCC
Weather
Sky
Clear
Wind Direction
East
Wind Speed
Light
Weather Comments
Cold temperatures overnight and clear skies after another round of precip ending by 2200 on 20200423. Temperatures rose rapidly by 1130 hours.
Snow Characteristics
New Snow Depth
6"
New Snow Density
Medium
Snow Surface Conditions
Powder
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments
Storm snow totals enhanced by altitude. 8000: skiff, 9000: 1 inch, 9500: 2 inches, 10,000 in Upper BCC: 4 inches, 10,000 Upper LCC: 6 inches. Riding was excellent in the dense new snow and the best riding was in the cold dry snow at the Upper Elevations on Moderate to Low Angled slopes. The Steeper terrain was still fun, but you could feel the bottom. It was, and is critical to find the smoothest slopes that don't have old tracks or avalanche debris. Wind had created Isolated Stubborn Wind Drifts up to 12 inches deep, with scouring down to the old m/f crusts in exposed terrain. All aspects got damp by early afternoon including northerlies with slope angles less than 25 degrees.
Red Flags
Red Flags
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
In protected areas the new cold snow was producing easy shears in the graupel above the old snow/new snow surface, but this was only noted in the morning hours when the snow was still cold and dry. By mid afternoon, Slope Cuts were easily producing Wet Loose Avalanches that were capable of entraining significant amounts of new snow that were sliding easily on the old m/f crusts. Roller ball activity was Widespread on all aspects by mid afternoon. Manageable Loose Dry Avalanches were Widespread in the new cold snow in the morning hours, and likely through the afternoon in the highest reaching Upper Elevation steep terrain on the Northerlies.
Avalanche Problem #1
Problem
Wet Snow
Trend
Decreasing Danger
Problem #1 Comments
See above, and this problem will likely have played itself out significantly by Saturday.
Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #2 Comments
New Snow/Loose Dry as described above will continue to be a manageable issue in the highest North facing steep terrain. And, even though the Isolated Wind Slabs observed on Friday were Stubborn and mostly Unreactive, there may still be a few very Isolated lingering Wind Slabs in the highest reaches of the Upper Elevation Northerly facing terrain on Saturday.
Despite the potential for the above Avalanche Problems on Friday, the Danger appeared to be Low and completely manageable with limited consequences in most terrain due to the limited amounts of new snow.
Today's Observed Danger Rating
Low
Tomorrows Estimated Danger Rating
Low