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Observation: Atwater Study Plot

Observation Date
1/14/2025
Observer Name
Kelly
Region
Salt Lake » Little Cottonwood Canyon » Atwater Study Plot
Location Name or Route
Atwater-Pole Line Pass
Weather
Sky
Few
Wind Direction
North
Wind Speed
Light
Weather Comments
Cold air temperatures with light to moderate north winds. The winds picked up and were transporting snow at the ridgeline near and above 10,000' in elevation. Low level canyon bottom clouds were burbling up through the afternoon.
Snow Characteristics
New Snow Depth
1"
Snow Surface Conditions
Powder
Damp
Snow Characteristics Comments
Snow surface on southerly facing slopes was starting to get damp and will be crusty tomorrow. Protected shady slopes were still soft.
Red Flags
Red Flags
Recent Avalanches
Wind Loading
Rapid Warming
Avalanche Problem #1
Problem
Wet Snow
Problem #1 Comments
I observed one avalanche (photo below) around 1:00PM on a southerly facing slope around 9,900'. This avalanche was shallow 6"-8" deep and maybe 30' wide running 100' vertical feet. It was a natural trigger and started as some sort of dry/wet loose in the steep rocks and then fanned out. It was a combination wet/dry avalanche that was right on the verge of both. I would imagine at lower elevation it would have been a wet avalanche. There was some wind drifted snow on southerly aspects above 10,000'. This was shallow and not much of a concern for today.
Avalanche Problem #2
Problem
Persistent Weak Layer
Problem #2 Comments
I also observed this avalanche in High Ivory on an east facing slope around 10,000' in elevation.
Snow Profile
Aspect
South
Elevation
8,800'
Slope Angle
6°
Comments
Hand dug snowpit above and Atwater SNOWPACK Modelling below:
The above is a combination of the SNOWPACK Modeling tool, snowpack temperatures from Atwater and a manual snowpit from SnowPilot. The goal is to continue to put manual snowpits in and see how closely they correspond to the SNOWPACK Model. This is still a work in progress and is a lot of information to process.
My thermometer is not calibrated to either the thermocouplers or the SNOWPACK model, and you can see it doesn't pull the surface temperature as well as the Atwater plot does (-12.6°C). We should see the same trend within the Snowpack model and Snowpilot. Same goes for trends with hand hardnesses and such. Notable today was the 0°C subsurface temp compared to the -6 °C air temperature and the Atwater surface temp of 12.6°C. There was no crust near the surface when I was digging, but the surface was starting to get some moisture and I imagine will have a surface crust ( and possibly some near surface facets) later today into tomorrow.
Read more about this project HERE.
Links:
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate
Coordinates