Small avalanche on North Peak of Waterhouse aka Powderhouse

Location Name: 
North face below treeline
Region: 
Luther Pass Area (including Job and Freel)
Date and time of avalanche (best estimate if unknown): 
Sun, 03/20/2011 - 12:45


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Observation made by: Public
Avalanche Observations
Avalanche Type: 
dry,slab,
Slope: 
30degrees
Trigger type: 
Skier
Crown Height: 
1 ft
Aspect: 
North
Weak Layer: 
Storm Snow
Avalanche Width: 
25ft.
Terrain: 
Below Treeline
Elevation: 
8 500ft.
Bed Surface: 
Storm Snow
Avalanche Length: 
30ft.
Number of similar avalanches: 
1
More detailed information about the avalanche: 

Skier one stopped at the top of a small convex rollover in tight trees at approximately 8500 feet on Powderhouse's north face to wait for skier two.  Upon stopping, the slope released immediately underfoot and slid approximately 30 feet down slope.  Skier one was able to step off the slab as it slid.

As skier two stopped slightly uphill, more shooting cracks propagated across the slope, but nothing else released.

The crown was approximately 14" on the skier's extreme right tapering to approximately 8" on skier's extreme left. The crown was approximately 25' in length.  The debris broke up into soft snow.  A detailed study of the bed surface and crown was not completed, but it was noted that the bed surface was storm snow.

On the skin up, debris from a larger slab avalanche was observed on the same aspect, slope and at approximately the same elevation.  The debris was covered with new snow and was probably triggered naturally during the early morning.  Additionally, shooting cracks were observed while skinning.

 

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