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Observation: Brighton Perimeter

Observation Date
12/9/2017
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Brighton Perimeter
Location Name or Route
Brighton Perimeter
Weather
Sky
Clear
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
Clear skies with mild temperatures for December. Winds were blowing in the high end of the Light range and only perceptable on the exposed ridges. No wind blown and or transport observed.
Snow Characteristics
Snow Surface Conditions
Faceted Loose
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments

In protected northerly ENE, N and WNW terrain there is up to 4 inches of NSF's resting on the rain crust. Unfortunately the NE and NW winds from the middle of the week adversely affected much of the terrain above 9000 feet. Sastrugi and wind swept surfaces exist on almost all exposed ridgelines at mid and upper elevations. Where the winds swept the snow away there is now the slick rain crust. South facing slopes with angles 25 degrees and greater got damp in the middle of the day and will be crusty from now on.

Red Flags
Red Flags
Cracking
Poor Snowpack Structure
Red Flags Comments
Poor snowpack structure exists throughout the entire snowpack with a mix of crusts, decomposing graupel, NSF's, DH, and mid pack advanced facets. The weakest facets that were yielding moderate CT scores were in the layes directly below the rain crust and in many places this layer was fist plus hard and up to 4 inches thick. At 9700 feet the snow pack has now settled to around 2 feet in height. Of note, in the upper elevation terrain on Claytons there were wind slabs that were exhibiting propagating cracks of up to 25 feet in length.
Avalanche Problem #1
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #1 Comments

See above and this problem is very isolated. In many locations the wind slabs appeared to be becoming more stubborn and less reactive. Wind slabs of up to 5 inches thick were observed.

Avalanche Problem #2
Problem
New Snow
Trend
Increasing Danger
Problem #2 Comments

In the steep shady areas still housing the previously cited NSF's the potential to initiate long running loose dry avalanches/sluffs remains likely. With the sustained high pressure in place this problem will continue to become more widespread and deeper until the winds blow out all the potential weak surface snow available for sustaining this activity.

Early season hazards appear to be the main concern, and quality riding is limited. The overall danger appears to be Low, yet any kind of fall and or small avalanche could push you into rocky consequences.

Today's Observed Danger Rating
Low
Tomorrows Estimated Danger Rating
Low