Wind Slabs on Tamarack Peak

Location Name: 
Tamarack Peak
Region: 
Mount Rose Area
Date and time of avalanche (best estimate if unknown): 
Sat, 01/21/2017 - 10:20
Location Map: 
United States
39° 18' 48.2508" N, 119° 54' 20.16" W
US


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap

Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
Dry
Slab
Slope: 
38degrees
Trigger type: 
Skier
Crown Height: 
2 ft
Aspect: 
Northeast
Weak Layer: 
Storm Snow
Avalanche Width: 
40ft.
Terrain: 
Near Treeline
Elevation: 
9 040ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
100ft.
Number of similar avalanches: 
2
More detailed information about the avalanche: 

Gentle ski kicks from low angle terrain on the ridgeline triggered wind slab avalanches on wind loaded N-NE facing slopes on the far east ridge of Tamarack Peak. Ski kicks also trigger widespread, long shooting cracks on wind loaded slopes in the area. The wind slabs failed on a density change in the storm snow and measured up to 2 ft in depth. Large cornices and continued wind transport were observed throughout the day in near and above treeline terrain. In more sheltered near and below treeline terrain, loose dry sluffs occurred resulting from ski cuts on steep terrain features in many areas. By early afternoon some minor shooting cracks started to occur on steep test slopes in sheltered non wind affected terrain but these cracks did not travel very far nor were they very widespread. Snowpit observations and tests targeting storm slab instabilities showed several density changes in the storm snow but did not indicate that fracture propagation along these layers was likely in sheltered non wind affected areas in the Tamarack Peak zone at that time. 

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Strong
Precipitation: 
Snow
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Light to moderate snow and strong winds throughout the day. some breaks in the clouds occurred periodically.