Observation: 10420

Observation Date
2/18/2025
Observer Name
Champion & Miller
Region
Salt Lake » Big Cottonwood Canyon » 10420
Location Name or Route
10420
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
West
Wind Speed
Light
Weather Comments
Overcast day with light snowfall for most of the day, occasional bursts of heavier snowfall, and intermittent periods of sun.
Snow Characteristics
New Snow Depth
2'
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments
Between 1–2' of new, low-density snow across much of 10,420'. Overnight, 3–4" of new snow accumulated on the skin track. As we climbed, the effects of the wind became more obvious, with all old tracks and skinners completely blown in and additional wind texture above 10,000'.
Red Flags
Red Flags
Recent Avalanches
Heavy Snowfall
Poor Snowpack Structure
Red Flags Comments
Lots of new snowfall and recent avalanches across the range. Once we stuck our shovels in the snow, we found a very poor snowpack structure.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Same
Problem #1 Comments
The primary goal of the day was to look at southwest aspects and see if we could get any results on the current persistent weak layers that exist across the entire Wasatch. We dug on a southwest aspect at 9,385' in an area that didn’t seem to have much wind effect or travel.
In our pit, we found primarily right-side-up snow sitting atop preserved stellars almost 2' down (similar to what Dave & Dave found in Little Cottonwood today), which rested on a thick layer of preserved graupel between 2–5mm in size. Beneath that was a stout melt-freeze crust, and below the crust, we found faceted grains of varying hardness from early season.
We got an ECTP28 failing below the graupel layer and beneath the stout crust within some of the smaller grain facets. I was surprised to see no failure within the graupel, despite it being widespread throughout Big Cottonwood. This continues to highlight the spatial variability across the range, but I’d give southwest aspects a second thought when stepping out.
SW Aspect - 9400' - Pit wall image, a few obvious layers including the preserved stellar, thick graupel layer, and a crust. Facets below the crust to the ground.
The large graupel found in the pit
ECTP28 - SW Aspect - 9400' - failing below both the graupel and the crust
Highlighting the crust within the pitwall -SW Aspect - 9400'
Pit profile - SW - 9400'
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable
Coordinates