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Grey Butte Test Pit

Location Name: 
Grey Butte
Region: 
Mt. Shasta
Date and time of observation: 
Sat, 12/24/2016 - 9:00pm
Observation made by: 
Forecaster
Red Flags:
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain

Location Map

United States
41° 20' 45.3084" N, 122° 11' 43.4868" W
See map: Google Maps
US

Snowpack Observations

Details

Height of Storm Total was 30cm.  Calm winds observed Near and Below Treeline during a tour from the Shasta Ski Park to the Grey Butte Weather Station.  Significant blowing of snow occurred above treeline and in upper elevation terrain.  Large pillows of snow  and wind slabs were growing throughout the day (see photo).  Winds kept snow moving above 9000ft and covered tracks between laps. Minor shooting cracks observed on several test slopes.  No avalanches or whoomphs observed.  Stability testing targeted the old snow/new snow interface, specifically the storm slab problem.  A test pit was dug on ENE slope at 7800ft.  The old snow/new snow interface was the layer of concern and was buried 40cm down from the surface (minor, uniform wind loading in the area).  In all stability tests, failure occurred on the new/old interface on a layer of rounding facets sitting just below a crust.  All extended column tests resulted in full propagation on this layer (see photo).  Compression tests failed with sudden collapse fractures.  

ECTP 12 down 40cm x2

ECTP13 down 40cm

ECTP 16 down 40cm

CT 12 down 40cm SC

Snow Pit Photos

Weather Observations

Details

Variable wind direction.  The advisory area has experienced primarily Southwest and Northwest winds the past 2 days.  However, Easterly winds have also played a significant roll in transporting snow and loading Westerly slopes.

Statistics

Cloud Cover: 
50% of the sky covered by clouds
Blowing Snow: 
Yes
Precipitation: 
Snow
Accumulation rate: 
Less than 1 in. per hour
Air temperature: 
Below Freezing
Air temperature trend: 
Static
Wind Speed: 
Light
Wind Direction: 
Southeast