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Observation: Scotts Backdoor

Observation Date
2/23/2022
Observer Name
John Lemnotis
Region
Salt Lake » Park City Ridgeline » Scotts Backdoor
Location Name or Route
Scotts back door
Weather
Sky
Obscured
Precipitation
Moderate Snowfall
Wind Speed
Calm
Weather Comments
Clear at the TH at 0900 with snow starting to fall by 1200. Steady S1 until returning to the cars at 1520. Winds remained calm throughout our tour up to 9400'
Snow Characteristics
New Snow Depth
8"
New Snow Density
Low
Snow Surface Conditions
Powder
Wind Crust
Snow Characteristics Comments
Guardsman's pass TH HN at 0900 was about 15cm. Snow continued throughout the day from 1200-1520 at a steady S1 rate. The storm snow was not cohesive yet and hadn't really formed a slab where there was no wind. Some minor wind drifted snow was evident along the side of of the guardsman's road in open terrain. Otherwise storm snow was light and rode well at mid elevations in protected terrain. We did dig down in a snow pit to isolate the new layer of concern (new/old interface down 15-30cm) and had no notable results. As stated before the storm snow simply did not have any slab characteristics and was weak over slightly stronger.
Red Flags
Red Flags
Recent Avalanches
Wind Loading
Poor Snowpack Structure
Red Flags Comments
The new old interface is the major concern. It is not covered by up to a foot of storm snow as well as fresh wind loads in specific areas. As we add more storm snow to the surface and a slab begins to form we will likely see avalanches sliding on the polar aspects N/O interface.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments
While this may not be reactive yet due to the light nature of the storm snow this layer will be a concern moving forward. I see an issue with fresh wind loads forming over the old NSF and being more reactive than the storm snow at this point. However, this could change with the addition of some new snow. For now avoiding avalanche terrain where a PWL is present and there is a slab on top is best for longevity.
Photo 1 - 20cm of storm snow sitting on top of fist hard faceted grains
Photo 2 - Subjective information but relevant. Rider jumping on the unsupported snow pack yielding a failure within the weak faceted grains down 25m.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
None
Coordinates