Skier triggered avalanche on the backside of Fireplug

Location Name: 
Fireplug
Region: 
Mount Rose Area
Date and time of avalanche (best estimate if unknown): 
Tue, 03/22/2011 - 08:45
Location Map: 
United States
39° 19' 32.8764" N, 119° 54' 12.1284" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path
Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
dry,slab,
Slope: 
40degrees
Trigger type: 
Skier
Crown Height: 
1 ft
Aspect: 
Northeast
Weak Layer: 
Storm Snow
Avalanche Width: 
250ft.
Terrain: 
Near Treeline
Elevation: 
9 000ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
650ft.
Number of people caught: 
1
Number of partial burials: 
1
More detailed information about the avalanche: 

This skier triggered avalanche occurred at about 8:45 am. The skier who triggered the slide was carried downhill and partially buried. He sustained some injuries, but reports suggest that they were not life threatening. He was evacuated to a hospital for treatment.

Some skier triggered cracking occurred while approaching this avalanche on nearby N-NE aspects. One natural avalanche that occurred either last night or early this morning was reported on a NE facing wind-loaded slope on the far east ridge of Tamarack Peak. This natural avalanche may or may not have been visible to the skier in this party due to clouds and low visibility at times during the day. The skier triggered slide occurred due a failure of the interface between a lighter layer of the most recent storm snow and a firmer layer below it. A slightly more dense layer of wind affected snow existed above this lighter layer of snow. The resulting fracture remained within the recent storm snow.

On nearby slopes in this area similar snowpack stratigraphy existed with a combination of light snow underneath heavier wind affected snow.

Photo 1: Initial trigger point

Photo 2: Avalanche crown at its widest point.

Photo 3: Looking down the slide path.

Photo 4: Looking up the slide path through the trees.

Pit: Crown profile

Video: Brief overview of the slide.

 

Snowpit or crown profile photo or graph: 
Avalanche Photos: 
Avalanche observation video: 

March 22, 2011 4:33 PM

Weather Observations
Blowing Snow: 
No
Air temperature: 
Below Freezing
Wind Speed: 
Light
Precipitation: 
Snow
Air temperature trend: 
Cooling
Wind Direction: 
Southwest
Accumulation rate: 
None
More detailed information about the weather: 

Scattered snow showers and light to moderate winds during the day. Very little new accumulation.