Avalanche Activity - Mt. Rose Area

Location Name: 
East Ridge Tamarack Peak
Region: 
Mount Rose Area
Date and time of avalanche (best estimate if unknown): 
Mon, 03/21/2011 - 11:30
Location Map: 
United States
39° 18' 55.4112" N, 119° 55' 4.7172" 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
Observation made by: Professional Observer
Avalanche Observations
Avalanche Type: 
dry,slab,
Slope: 
35degrees
Trigger type: 
Skier
Crown Height: 
2 ft
Aspect: 
North
Weak Layer: 
Storm Snow
Number of similar avalanches: 
4
More detailed information about the avalanche: 

Several small, D1+, avalanches in just below treeline windloaded north aspects at 9400' and also up off the ridgelines at higher elevations.  Cracking, shooting cracks and collapsing all common in wind loaded terrain.  Most of these triggered with a small ski kick.  ECT's and PST's tests were showing signs that the storm snow is gaining some strength but all informal tests pointed towards easy triggering of windslabs in NW-E aspects at or above treeline.  Cornices are built out very far and very sensitive to the weight of a skier.  No natural avalanche activity seen in this area today.

Photo#1: Shooting crack 25' long.

Photo#2:  9700' north aspect, 38-40 degrees, triggered by intentional cornice drop.

Photos #3:  9400' north aspects, slab triggered by intentional small ski kick.

Photo#4:  9700' north aspect, 38-40 degrees.  Both slabs triggered by intentional cornice drops.

All slab failures were 1' in treeline terrain and up to 2' deep on the exposed ridge at upper elevations. 

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

mtrose2011 3 21 019

Weather Observations
Blowing Snow: 
Yes
Air temperature: 
Below Freezing
Wind Speed: 
Moderate
Precipitation: 
Snow
Air temperature trend: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Light snowfall in the morning tapering off by midday.  Moderate SW winds increasing in speed as the day went on moving moderate amounts of snow.  Cloud cover would vary from dense low cloud cover to small periods of sun.