Observation: Big Cottonwood Canyon

Observation Date
1/6/2022
Observer Name
Greg Gagne
Region
Salt Lake » Big Cottonwood Canyon
Location Name or Route
Guardsman Pass / 10,420' / Butler Fork
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
West
Wind Speed
Light
Weather Comments
Very warm and humid at lower elevations with improving conditions up high. Still warm at 10K with 0C. Winds have relaxed quite a bit and only had a few gusts atop 10,420'
Snow Characteristics
New Snow Depth
14"
New Snow Density
High
Snow Surface Conditions
Damp
Snow Characteristics Comments
Difficult to gauge new snow depths given recent winds and rapid settlement, but roughly 30-40 cms new snow above 10,000'.
Red Flags
Red Flags
Recent Avalanches
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
A few big avalanches over the past day or two with rapid warming at low elevations and creeping into mid elevations.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #1 Comments
The PWL remains our biggest concern, but we may be getting close to having this problem go dormant. I was finding about 2 meters on top of the PWL where I was looking today above 9,000' with a strong slab on top of the facets. With such good riding conditions on lower-angles, I'm not ready to even think about getting onto steep northerlies.
Comments
Looked at snow today at the upper elevations and lower elevations:
Upper Elevations: On Wednesday I was finding the interface at the interface between the storm snow and the old snow to be reactive, with cracking and easy shears. Today, I had dug several pits between 9,000' and 10,500' and everything showed instabilities to have settled out. This is no surprise given how warm and dense the storm snow is. I was also finding recent wind drifts to be unreactive to ski cuts.
Low Elevations: Rain/snow lines touched as high as 7,500 or even 8,000 and the top 10-20 cms of snow at the low elevations is saturated. I ventured into the lower reaches of Butler Fork and was finding dry snow ~20 cms down from the surface and this dry snow could be a reactive weak layer if temperatures warm at the lower elevations on Friday. My thinking Thursday night is to list Wet Snow as an avalanche problem for lower elevations on Friday.
Photos are of pits at (1) upper elevation, and (2) lower elevations.
Discussion of my thinking of current snowpack structure at the mid and upper elevations. (Excuse the vertical alignment)
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable