Stanislaus Wall above Hwy 108 W

Location Name: 
Stanislaus Wall
Region: 
BWRA
Date and time of avalanche (best estimate if unknown): 
Sun, 12/16/2018 - 02:33
Location Map: 


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap

Observation made by: Avalanche Specialist
Avalanche Observations
Avalanche Type: 
Dry
Slab
Slope: 
44degrees
Trigger type: 
Natural
Crown Height: 
3 ft
Aspect: 
North
Weak Layer: 
Other - explain below
Avalanche Width: 
50ft.
Terrain: 
Above Treeline
Elevation: 
9 200ft.
Bed Surface: 
Other - explain below
Avalanche Length: 
250ft.
Number of people caught: 
0
Number of partial burials: 
0
Number of full burials: 
0
Did the avalanche hit a building, vehicle, or structure?: 
No
More detailed information about the avalanche: 

This piece of terrain is complex & will avalanche with regularity when we receive precipitation. It is in the main travel corridor from the Stanislaus NF, or West side of Sonora Pass, it eventually entering the BWRA. This is an obvious slide path with a prominent terrain trap at its terminus. The avalanche is a result of wind driven snow that accumulated in a hanging cornice that ultimately broke free & traveled down the slope entraining more snow on its descent. Although its overall size is not dramatic, the size & density of the chunks that remained intact is impressive, large blocks that are nearly 3' thick. R1D2 on a North aspect near treeline.

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
25% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Moderate
Precipitation: 
None
Air temperature trend: 
Static
Wind Direction: 
South
Accumulation rate: 
None
More detailed information about the weather: 

Mostly sunny skies with moderate to gusty strong winds from the West to South. Gusts were strong enough to scour the snow surface & deposit dirt in valley bottoms. Most snow was not readily available for transport, making strong ridgetop winds the mechanism for this event. The snow surface has a "scalloped" appearance, or any old snow not condensed by travel tracks can be harvested by gusty winds.