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Observation: The Spire

Observation Date
1/8/2024
Observer Name
Gagne
Region
Salt Lake » Little Cottonwood Canyon » White Pine Gulch » The Spire
Location Name or Route
White Pine Gulch - The Spire
Weather
Sky
Broken
Precipitation
Light Snowfall
Wind Direction
Northwest
Wind Speed
Light
Weather Comments
Periods of light snow showers.
Snow Characteristics
New Snow Depth
18"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments
*Very* low-density powder. Storm totals since Sunday are 30-45 cms.
Red Flags
Red Flags
Recent Avalanches
Poor Snowpack Structure
Red Flags Comments
Three natural soft slab avalanches on north aspects off of the Spire between 9,000 - 9,500'.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments
The poor structure is in place and all we need is a denser slab on top of the December Drought Layer (DDL) which is buried 30-60 cms deep. Strong winds and heavy snowfall forecast for Tuesday may give us that slab.
Comments
Traveled up White Pine Gulch to the north-facing trees below the Spire. What caught my attention were three soft slab avalanches:
- northwest aspect at 9,000' (photo below)
In areas without a denser slab on top, the low-density snow is only sluffing within the storm snow. But where there is a slab (likely due to wind-loading), many natural soft slab avalanches are being reported.
It is difficult to perform an ECT with such soft snow on top of the weak layer, but a PST on a north-facing slope where the PWL was buried down 40 cms produced PST 15/100 END and PST 50/100 END, which indicates fracture propagation is likely. Photo below.
Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
High
Coordinates