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Small Wind Slab Avalanche in Powder Bowl

Location Name: 
Green Butte, Mount Shasta
Region: 
Mt. Shasta
Date and time of avalanche (best estimate if unknown): 
Tue, 01/05/2021 - 12:00pm
Observation made by: 
Forecaster
Red Flags:
Recent loading by new snow, wind, or rain
Obvious avalanche path

Location Map

96067 Mount Shasta , CA
United States
41° 22' 11.9568" N, 122° 12' 46.4436" W
See map: Google Maps
California US

Avalanche Observations

Details

A small (R1/D1) wind slab avalanche was snowboarder-triggered in steep rocky terrain on the east/southeast flank of Powder Bowl on Green Butte.  The crown was approximately 6 inches (15 cm) in height and spanned 20 ft. The runout length was 30 ft.  The one finger-hard slab failed on a density change above the new/old snow interface. 

As a reminder, even a small avalanche like this one can have consequential results if you are caught and carried into or over a terrain trap (e.g., gully, rocks, cliff, crevasse). 

Avalanche Classification Code: SS-ASu-R1-D1-S

Photos

Characteristics

Avalanche Type: 
Slab
Trigger type: 
Snowboarder
Slope: 
40degrees
Aspect: 
Southeast
Terrain: 
Above Treeline
Weak Layer: 
Storm Snow
Bed Surface: 
Old Snow
Crown Height: 
Less than 1 ft
Avalanche Width: 
20ft.
Avalanche Length: 
30ft.
Number of people caught: 
0
Number of partial burials: 
0
Number of full burials: 
0

Weather Observations

Details

Our Gray Butte weather station has recorded 13 hours of moderate (17 - 25 mi/hr) west/northwest winds in the last 24 hours.

Statistics

Cloud Cover: 
25% of the sky covered by clouds
Blowing Snow: 
Yes
Precipitation: 
None
Accumulation rate: 
Less than 1 in. per hour
Air temperature: 
Below Freezing
Air temperature trend: 
Warming
Wind Speed: 
Moderate
Wind Direction: 
West