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Observation: Salt Lake

Observation Date
12/20/2020
Observer Name
B
Region
Salt Lake
Location Name or Route
Mid Little Cottonwood Canyon
Weather
Sky
Overcast
Precipitation
Light Rain
Wind Speed
Calm
Weather Comments
Mostly Clear skies transitioned to Overcast by 1230. Above normal seasonal temperatures rising above freezing, and then sporadic periods of very light misting rain in the areas traveled: LOWER ELEVATIONS observed (7000 to 8000).
Snow Characteristics
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments
At 1300, the snow surface on Low angle terrain at 7800 feet WNW became slightly damp, but NW and N aspects remained cold dry snow up to 1600. At that point, we exited and the misting rain began around 1700. New snow has settled significantly and the riding is still good, but much more dense and thick than the past few days. The Upper Elevations likely are not as adversely effected, yet reports from Mineral Basin indicate rapid warming and challenging riding in Wet Snow conditions.
Red Flags
Red Flags
Recent Avalanches
Cracking
Collapsing
Poor Snowpack Structure
Red Flags Comments
More reports of Recent Avalanches continue to dribble in. The Poor Snowpack structure is obvious, yet first time observing Low Elevation Terrain yielded interesting results. Multiple Snow Pits from 7600 to 8000 on W through NW aspects indicated reactive buried SH at the pre-storm interface with ECTP5 through 15 results. CTE SC's were also observed. The "Grey Stripe" was obvious, and the grains were very observable. Cracking and Collapsing Widespread. Of Note: This SH problem may be more Widespread, and locations like Lambs Canyon may house the same issues. High RH values from Valley Inversions appear to migrate up the lower parts of the Canyons and contribute to this type of Grain Growth.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments
See abovce
Avalanche Problem #2
Problem
Wet Snow
Trend
Increasing Danger
Problem #2 Comments
Rain Rapid Warming and Intermittent Solar appeared to all contribute to Isolated Wet Loose, on the Southerlies up to 8000.
No overnight refreeze: Sunday to Monday with Temperatures hopefully dropping by mid day on Monday. If forecast verifies, this Wet Issue should abate. But, for the morning hours at Low Elevations this issue may have become more Widespread.
FINALLY: ROOF AVALANCHES DISPERSING THE DECEMBER STORM IS LIKELY.
High consequence Moderate.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate