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Unstable cornices and wind slab avalanche

Submitted by nmeyers on Wed, 02/22/2017 - 7:04am
Location Name: 
Eddy Range - Parks Creek summit area
Region: 
Mt Eddy
Location Map: 
United States
41° 20' 42.0936" N, 122° 30' 44.6508" W
US
Observation made by: 
Forecaster
Date and time of avalanche (best estimate if unknown): 
Tue, 02/21/2017 - 11:00am
Red Flags: 
Recent avalanche activityWhumphing noises, shooting cracks, or collapsing
Avalanche Observations
Avalanche Type: 
Slab
Slope: 
37degrees
Trigger type: 
Natural
Crown Height: 
1 ft
Aspect: 
North
Weak Layer: 
Unknown
Avalanche Width: 
150ft.
Terrain: 
Above Treeline
Elevation: 
7 800ft.
Bed Surface: 
Unknown
Avalanche Length: 
900ft.
Number of people caught: 
0
Number of partial burials: 
0
Number of full burials: 
0
More detailed information about the avalanche: 

Two easily triggered cornices features in areas of little consequence were observed yesterday, 2/20. Also, a natural wind slab avalanche was observed on a northerly facing slope above treeline. A full investigation was not conducted. This avalanche was viewed from afar. 

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
Snow
Air temperature trend: 
Cooling
Wind Direction: 
South
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

A very alpine feel was present up in the Eddies yesterday with sunlight filtering through thin clouds and more dense clouds passing by blocking the sun from time to time. Periods of very light snow and graupel fell. No accumulation. The snow below 6,800 feet began to become heavy and even formed a slight temperature crust later in the day. This will likely be a zipper crust now. Above 7,000 feet, snow surfaces were smooth and soft. From 6,500 to 7,000 feet, this elevation band is transitional. Winds were not noticeable below treeline. Near treeline a few gusts came through but otherwise was nice. Above treeline, moderate winds blew out of the south. Temperatures were below freezing all day.