Several Avalanches in Bronco Chutes

Location Name: 
Bronco Chutes
Region: 
Mount Rose Area
Date and time of avalanche (best estimate if unknown): 
Fri, 12/16/2016 - 07:00
Location Map: 
United States
39° 19' 4.9764" N, 119° 57' 24.2604" W
See map: Google Maps
US


Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap
Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
Dry
Slab
Trigger type: 
Unknown
Crown Height: 
3 ft
Aspect: 
North
Weak Layer: 
Old Snow
Avalanche Width: 
200ft.
Terrain: 
Above Treeline
Elevation: 
9 640ft.
Bed Surface: 
Old Snow
Avalanche Length: 
800ft.
Number of similar avalanches: 
5-10
More detailed information about the avalanche: 

Several avalanches released in the Bronco Chutes area near the end of the 12/15-12/16 storm. Many of these slides occurred on N-NE aspects and had crowns in the 2 to 4 ft. range. They seem to have failed on the facets near the base of the snowpack. Out of several ECTs and PSTs performed near these crowns, only one ECT propagated on that layer. That ECTP was done near a rock outcrop and had rocks at the base of the column. All of the other tests either did not fracture or did not propagate across or up the columns. This snowpit data combined with other observations seemed to indicate that the time for this specific instability had passed by 12/19. Another avalanche was observed at 39.315209, -119.952217. This slide seemed to have failed above the 12/15 rain crust, the crown was filled in, and the debris covered with snow. 

Avalanche Photos: