Observation: Little Cottonwood Canyon

Observation Date
4/1/2025
Observer Name
Gagne/Johnston
Region
Salt Lake » Little Cottonwood Canyon
Location Name or Route
Natural Avalanche Cycle - Upper Little Cottonwood
Weather
Sky
Obscured
Precipitation
Heavy Snowfall
Wind Direction
Northwest
Wind Speed
Moderate
Weather Comments
Extended periods of S-5 snowfall (2"/hr). Winds were averaging in the 20's mph, an ideal speed for drifting snow.
Snow Characteristics
New Snow Depth
18"
New Snow Density
Low
Snow Surface Conditions
Powder
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Wind Loading
Cracking
Red Flags Comments
Widespread cracking and easy to initiate an avalanche on a slope approaching 35° or steeper.
Avalanche Problem #1
Problem
New Snow
Trend
Decreasing Danger
Problem #1 Comments
The storm snow was reactive, especially during any period of high precipitation intensity (PI), failing in different density inversions within the storm snow. In this screenshot from the Collins weather station, you can see the period of heavy snowfall when the natural avalanche cycle occurred.
Avalanche Problem #2
Problem
Wind Drifted Snow
Trend
Decreasing Danger
Problem #2 Comments
Any slope that was wind-drifted was very sensitive, with drifts up to 45 cms (18").
Comments
Travel today was East Bowl Pass to Honeycomb, with several laps down into Michigan City. There was widespread cracking, and we were able to ski cut many slopes and trigger small avalanches. There was some clearing when exiting at 12:30, and we noted a widespread natural avalanche cycle that occurred in the morning, during periods of heavy snowfall. I counted over 20 natural avalanches, with the largest being all of north-facing Grizzly Gulch, likely 1,000' wide. The avalanches were 15-30 cms deep (6-12"), failing within different density inversions, although one crown was up to 45 cms (18") deep. Avalanches were on all aspects and included several off of the south/southwest facing Grizzly Cup and Michigan City Gully, and on numerous steep test slopes.
Photos of the various natural avalanches we encountered:
The danger was solid Considerable during the morning hours, but new snow instabilities quickly settle out. Unless the sun comes out on Wednesday, the danger should be lower as the new snow will be less sensitive.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Moderate
Coordinates