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Grey Butte NE Aspects

Location Name: 
Grey Butte NE Aspects
Region: 
Mt. Shasta
Date and time of observation: 
Tue, 01/10/2017 - 11:00pm
Observation made by: 
Professional Observer
Red Flags:
Recent avalanche activity

Location Map

United States
41° 20' 44.4372" N, 122° 11' 43.5156" W
US

Snowpack Observations

Details

A tour on Grey Butte saw about 1 in / hr of snow, moderate to strong SW winds, and evidence of wind loading on E and NE aspects. The rain crust from the 1/8/17 rain event was witnessed throughout all elevations, at a depth of 50-64 cm (20-25 in). Skis did not penetrate this layer and no whumphing was heard. A snowpit was dug on a sheltered ENE aspect of Grey Butte just below the weather station with the following characteristics:

Aspect: ENE

Angle: 30°

Elevation: 7976

Height of Snow (HS): 377 cm (148 in, 12.4 ft)

New Snow From 1/8 rain event: 64 cm (25 in)

New Snow From 1/6 storm event: 90 cm (35 in, 3 ft)

Stability Tests:

CT7; Sudden Planar & CT10; Resistant Planar @ 20cm

CT13; Resistant Planar; & CT14; Non-planar Break @ 40cm

CT21; Non-planar Break; & CT24; Sudden Collapse @ 70 cm

ECTN10 @ 20cm

ECTN16 @ 40 cm

ECTP27 @ 70 cm

Whereas stability tests on this aspect did not yield concerning unstable results, a similar aspect (NE, 35-40°) that was subject to strong SW winds yielded an easily controlled ski triggered avalanche (see pics). Controlled ski trigger caused a cornice fall which triggered a wind slab avalanche entraining loose snow beneath. Destructive size was about D1.5 -- might lead to burial. Crown was about 20 in.

Though visibility was poor, we think we saw signs of a what was probably a D1.5 avalanche that may have occurred early in the 1/6 storm cycle on the NW aspect of the ridge-line between Grey Butte and the weather station.

Skiing was great!

Photos

  • Windloading
  • Human Triggered Avalanche - Location

Weather Observations

Statistics

Cloud Cover: 
100% of the sky covered by clouds
Blowing Snow: 
Yes
Precipitation: 
Snow
Accumulation rate: 
Greater than 1 in. per hour
Air temperature: 
Below Freezing
Air temperature trend: 
Warming
Wind Speed: 
Light
Wind Direction: 
North