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Observation: Scotts Backdoor

Observation Date
12/12/2024
Observer Name
Kelly, Kelly
Region
Salt Lake » Park City Ridgeline » Scotts Backdoor
Location Name or Route
Guardsman- Park City Ridgeline- Scott's Back Door
Weather
Sky
Few
Wind Direction
Southwest
Wind Speed
Moderate
Weather Comments
High clouds with a dropping cloud deck. Lenticular clouds over the western mountains. Winds were light gusting to moderate from the west-southwest at one weather station on the Park City Ridgeline ridge and east-southeast at another weather station. Air temperatures were hovering right around freezing at 32°F.
Snow Characteristics
Snow Surface Conditions
Faceted Loose
Snow Characteristics Comments
Faceted loose snow surface in most locations where there was snow.
Red Flags
Red Flags
Poor Snowpack Structure
Avalanche Problem #1
Problem
Persistent Weak Layer
Snow Profile
Aspect
West
Elevation
9,400'
Comments
We found 17" (44cm) snow on a west facing slope at 9,470'. There was a slight very weak crust just below the surface that had some angulated and striated facets underneath it. Above this crust was a mix of broken stellars with some light wind affected snow. The photo below shows the distinct line where we found this melt-freeze crust (crystal card marks location) . This location was a low angle slightly sheltered meadow and the snowpack was so weak that we weren't able to do any sort of tests. This is the sort of meadow where I would look for collapsing, whumpfing, and cracking after the next storm.
What does the melt-freeze crust mean? We thought that the snowpack was so weak that the near surface crust wouldn't matter all that much as the bigger concern was the weaker faceted snow midpack. We thought that in the future the failure with enough snow or wind would be on a steeper slope in the middle of the snowpack and that the upper crust wouldn't be a player. Right now throughout this zone there are three layers of concern:
  • Facets near the ground
  • Facets near the surface
  • In some locations; facets in the middle of the snowpack above a basal crust
As we start to see a change in weather, any slope greater than 30 ° in steepness that had old snow on the ground is suspect and I will be very tentatively looking for safe places to travel as we get more snow and wind in the future. On slopes with no snow we'll be back to dealing with a thin snowpack and hitting rocks, stumps, and summer surface is what I will be looking to avoid.
We met up with the Park City Crew for one of their patrol avalanche classes and looked at some of the recent activity on their side of the ridge. The below slide was an explosive controlled avalanche that was within the Park City Resort Boundary. This avalanche is similar to what we were seeing in Upper Days and Silver Fork at the end of November. It failed on a primarily north facing 39° slope at 9,990'. As Park City prepares their ski area terrain please respect ski area boundaries. You can access the most updated resort travel information HERE.
Photo of an explosive controlled avalanche within the Park City boundary (in bounds) in closed terrain. Thanks to the Park City Snow Safety Team for letting us join them for the class and to take a look at this most recent avalanche.
Today's Observed Danger Rating
Low
Tomorrows Estimated Danger Rating
Low
Coordinates