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Observation: Brighton Perimeter

Observation Date
11/29/2018
Observer Name
B
Region
Salt Lake » Big Cottonwood Canyon » Brighton Perimeter
Location Name or Route
Brighton Perimeter
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
Southeast
Wind Speed
Moderate
Weather Comments
Cloud deck got thick by 0830, and the SE winds ramped up considerably by 0930 in the Alpine. Moderate to Instense blowing snow and or transport observed above 9600 feet in exposed terrain. Temperatures appeared moderate and were dropping throughout the day.
Snow Characteristics
New Snow Depth
5"
New Snow Density
Medium
Snow Surface Conditions
Powder
Wind Crust
Melt-Freeze Crust
Snow Characteristics Comments
Attempted to get out early and hit the Alpine before the winds ramped up, but by 0830 the winds had risen to the moderate level in the upper elevations, and appeared to be escalating in velocity throughout the morning hours. As a result, abandoned this idea and headed back down to the mid elevation protected areas. Ankle deep powder riding was superb on moderate to low angle terrain. Old m/f crusts were observed on due south aspects that had slope angles 25 degrees and greater. 10 cm of snow overnight with another 4 cm by 1300 hours as S1 to S2 snow fall rates were observed.
Red Flags
Red Flags
Recent Avalanches
Wind Loading
Cracking
Collapsing
Poor Snowpack Structure
Red Flags Comments
Poor snowpack structure is obvious and can be found on all aspects except due south from Brighton and higher. Collapsing and cracking has lessoned when compared to two days ago, but was still able to initiate this red flag in numerous locations. Of note, the overlying slab appears to be stiffening and providing a minimal and insecure bridge over the buried faceted layers. Left the alpine before wind slab development had a chance to get going, but with substantial snow available for transport, it appeared obvious that NW, N and NE aspects were getting loaded above 9600 feet in exposed terrain.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments
As has been noted by all other observations, the October snow is extremely weak. This problem now appears even more dangerous than it was several days ago when it was very easy to remotely trigger avalanches. At this point, the overlying slab may allow travelers to venture out further on to slopes with angles approaching the upper 30's in steepness before collapse failure may be initiated. And, this problem may be increasing as the winds new snow may provide more load throughout the day.
Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Increasing Danger
Problem #2 Comments
The southerly winds were obviously loading slopes that have the worst structure, and natural avalanches may have been possible later in the day.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable