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Observation: Silver Fork

Observation Date
12/21/2015
Observer Name
Brackelsberg
Region
Salt Lake » Big Cottonwood Canyon » Silver Fork
Location Name or Route
Silver Fork Meadow Chutes
Weather
Sky
Overcast
Wind Direction
Southwest
Wind Speed
Light
Snow Characteristics
New Snow Depth
7"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments

New snow ranged from ~3" overnight in the bottom of Silver Fork to ~7".

On the ridgeline, there was a small amount of graupel within the new snow.

Red Flags
Red Flags
Poor Snowpack Structure
Red Flags Comments
The ridge line was not windloaded in the morning, but the wind was picking up during the morning so I would expect that it was windloaded by afternoon. The snowpack was consistent with elsewhere being very faceted, but I found a lot of variability in the slab above the facets (see photos)
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments

The slab was variable in location and hardness. See photos for details on the slab.

The reactiveness of the slab will likely increase with additional snow load.

Comments

I was very surprised at the spacial variability. I did 3 quick and pits between 9400' NE and 9600' E and found significant differences in the density of the slab and thickness of the ice/rime crust.

Photo 1 was ~9,400' NE. There was very little slab and the ice/rime crust was very weak. There was another weak crust above the facets and just below where the very weak slab.

Photo 2 was just below the ridge (~9,600'). This had a dense slab above facets with a thicker ice crust. This photos also has the facets on this hand pit

Photo 4 was another pit east facing about 9,500'. The ice crust here was stronger than higher up and there was also another ice crust just above the facets. This photo also has the facets from this area.

Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
High