Observation: Emma Ridges

Observation Date
12/11/2021
Observer Name
Meisenheimer/Champion/Leven
Region
Salt Lake » Little Cottonwood Canyon » Emma Ridges
Location Name or Route
Flagstaff to East Pass
Weather
Sky
Scattered
Weather Comments
It was a beautiful morning with clear skies and cold temperatures. About noon, clouds streamed in from the west, and the southerly winds picked up.
Snow Characteristics
New Snow Depth
2'
New Snow Density
Medium
Snow Surface Conditions
Powder
Melt-Freeze Crust
Snow Characteristics Comments
Powder snow on all aspects and elevations.
Red Flags
Red Flags
Recent Avalanches
Wind Loading
Cracking
Collapsing
Poor Snowpack Structure
Avalanche Problem #1
Problem
Persistent Weak Layer
Problem #1 Comments
We traveled along the ridge between Big Cottonwood and Little Cottonwood from Flagstaff to East Pass Silver Fork. In our travels, we had many thunderous collapses and shooting cracks on the northerly (shady) side of the mountain.
It was pretty clear that if you dropped in, you would most likely trigger an avalanche that was 1-3' deep and a few hundred feet wide. The old October and November snow is very loose and faceted along the entirety of the upper elevation northerly aspects in Day's and Silver Fork. I will be avoiding this terrain for some time.
Don't be fooled into thinking the snow is stable. If you're traveling on off aspects (those without faceted snow), it could be easy to think the snowpack is stable. However, if you change your elevation or aspect to one that has weak faceted snow you will likely trigger an avalanche.
Avalanche Problem #2
Problem
Wind Drifted Snow
Problem #2 Comments
Southerly winds started to transport snow around noon. However, it was confined to the upper elevation peaks for now. I think all the new snow instabilities are gone, and now avalanches will be found in places where snow is being drifted from the wind or on a slope with old, weak-faceted snow.
Video
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable