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Observation: Brighton Perimeter

Observation Date
12/28/2018
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Brighton Perimeter
Location Name or Route
Brighton Perimeter/Brighton Back Bowls/Twin Lakes/Patsy Marley
Weather
Sky
Clear
Wind Direction
Northeast
Wind Speed
Light
Weather Comments
Single digit temperatures throughout the day. Clear skies in the am with few for periods during the mid day. Winds were light out of the NNE until mid day when they shifted to the NW. No wind blown and or transport observed.
Snow Characteristics
New Snow Depth
3"
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments
Periods of light density snowfall at S1 rates overnight with 8 cm in the past 24 hours. New snow keeps adding up in a right side up overall snowpack. Exposed NW, N and NE upper elevation terrain had areas of wind sculpting. Wind slabs were observed on NE ridge lines. Overall, the vast majority of the terrain has excellent mid winter bottomless riding.
Red Flags
Red Flags
Recent Avalanches
Wind Loading
Poor Snowpack Structure
Red Flags Comments
Snow pack observations in the upper Cottonwoods continues to support the assumption that the structure is turning around and healing. Pit dug on N aspect at 9500 feet with slope angle of 24 degrees indicated that the preexisting mid pack sensitive layers are becoming significantly less reactive. The graupel layer of concern is strengthening as well as the buried NSF's from early in December that were noted and observed just 5 days prior. Storm Slab reactive density interfaces from the past 4 days of snow fall continue to show signs of sensitivity; and small loose dry avalanches/sluffs were still an problem/issue today on steep terrain.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #1 Comments
No sensitive fresh wind slabs were encountered in our travels, yet the data from the remote weather stations in the upper elevation exposed terrain appeared to indicate a distinct possibility for this issue.
Avalanche Problem #2
Problem
New Snow
Trend
Decreasing Danger
Problem #2 Comments
See above regarding Loose Dry Avalanches. The frigid temperatures may keep this issue alive on very steep terrain, yet overall this issue should be decreasing.
Despite the presence of Persistent Slab Avalanches, the fact remains that the snow pack structure outside of the upper Cottonwoods is suspect in the shallower snow pack regions. In the upper Cottonwoods repeater slide paths also remain suspect, as well as very steep rocky terrain features.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate