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Observation: Butler Fork

Observation Date
12/30/2022
Observer Name
Grainger, Kelly
Region
Salt Lake » Big Cottonwood Canyon » Butler Fork
Location Name or Route
Butler Fork
Weather
Precipitation
Light Snowfall
Wind Direction
Southwest
Wind Speed
Moderate
Weather Comments
Precipitation began midday, gusty ridgetop winds moderated slightly with precipitation.
Snow Characteristics
Snow Surface Conditions
Powder
Dense Loose
Melt-Freeze Crust
Snow Characteristics Comments
Surface conditions are mostly settled powder on top of rain crust at low elevations and a smooth, high-density frontal snow layer up higher. South-southeast through Southwest aspects got enough solar radiation yesterday to develop a breakable zipper crust. Ridgetops will see continued loading through this event.
Loading on Wilson Ridgetop
Red Flags
Red Flags
Recent Avalanches
Wind Loading
Poor Snowpack Structure
Red Flags Comments
Traveled up Butler Basin to the Wilson shoulder today with the intent of looking at low and mid elevation structure as this next weather event comes in. Overall the rain on the front end of this week's Southwest flow affected much of the snowpack below 8000' and layers are damp throughout. Higher up, however, both NW and Southerly aspects showed a mix of layering with crusts, graupel and small-grained facets forming possible failure planes. Pits throughout the drainage showed a few stubborn results on both of the last significant storm interfaces as well as the late Nov. facets.
Avalanche Problem #1
Problem
New Snow
Trend
Increasing Danger
Avalanche Problem #2
Problem
Persistent Weak Layer
Snow Profile
Aspect
South
Elevation
9,200'
Slope Angle
31°
Comments
South facing pit below Wilson Peak. Failure at 57cm was later (27 taps) but had more snap to it. Surprising amount of snow for the aspect, elevation, and location. Appears to be a healing snowpack-although PWL was hard to find the consensus was that there were some faceted grains amongst the clustered slush 57cm from the ground.
Snowpit 7300' in Butler Gully
SW aspect above the access trail
Slope angle was 45 degrees.
Failure after ECTX @43cm off the ground under the dirt layer. Facets going to rounds. This snowpack was affected by rain.
Photo below of failure 43cm off ground after ECTX
We also looked at the avalanche in Scary Gully from 12.18.2022 and updated that observation with a crown profile.
This avalanche failed around the ice layer 28cm from the ground.
Black Crystal card denotes ice layer which was the bed surface of this avalanche.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
High
Coordinates