Natural Avalanches on East Ridge Tamarack Peak

Location Name: 
East Ridge Tamarack Peak
Region: 
Mount Rose Area
Date and time of avalanche (best estimate if unknown): 
Sun, 02/09/2014 - 13:00
Location Map: 
United States
39° 18' 46.8864" N, 119° 54' 42.7968" 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: 
38degrees
Trigger type: 
Natural
Aspect: 
North
Weak Layer: 
Storm Snow
Avalanche Width: 
400ft.
Terrain: 
Near Treeline
Elevation: 
9 300ft.
Avalanche Length: 
200ft.
Number of similar avalanches: 
2
More detailed information about the avalanche: 

Widespread, large whumpfing and collapsing on all aspects and elevations in this area.  A large density change in the recent storm slab could easily be felt with a ski pole probing into the snow.

Test pit done on Far East Ridge of Tamarack Peak at 9154', 12:30pm, N aspect, 28 degree slope just below ridge but in treeline terrain.  Consistent ECTP's and CT failure down 40cm from surface on a storm snow density change.  Air temp 0c, M-SW winds with some wind loading at this location during a small break in the storm.  HS 185cm.  Loose 3mm facets at snowpack base observed at this location but not tested.

Video:  ECTP-12 down 40cm from surface at test pit location.   

Photo#1:  Natural avalanche partially filled in.  9200', NE aspect, 35 degree slope on the East Ridge of Tamarack Peak

Photo#2: Skier triggered cornice drop on slope initiated small wind slab avalanche that went down slope 50-75'.  9300', N aspect, 30-35 degrees.

Photo#3 and #4: D2 Natural avalanche on East Ridge of Tamarack Peak partially filled in by storm snow.  9300', 35-40 degree slope, N aspect.  400' wide with large shooting cracks into lower angle terrain with avalanche running 200-300' downslope.  2-3' crown line.  Photo #4 shows rocks and ground cover but could not confirm if avalanche stepped down into older snow layers.   

Avalanche Photos: 
Avalanche observation video: 

EastRidgeTam2014 2 9 001

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
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: 

A small break from late morning into the early afternoon and then the storm moving back in.  Snow level around 7000' at 3pm.