Remotely Triggered Avalanches and Natural Avalanches Near Bards Bowl

Location Name: 
Bards Bowl
Region: 
Bear Valley Area
Date and time of avalanche (best estimate if unknown): 
Wed, 01/13/2016 - 11:30
Location Map: 
United States
38° 29' 38.2812" N, 120° 0' 28.7892" 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: 
35degrees
Trigger type: 
Natural
Crown Height: 
2 ft
Aspect: 
Northeast
Weak Layer: 
Old Snow
Avalanche Width: 
400ft.
Terrain: 
Near Treeline
Elevation: 
8 280ft.
Bed Surface: 
Old Snow
Avalanche Length: 
200ft.
Number of similar avalanches: 
2
Number of people caught: 
0
Number of partial burials: 
0
Number of full burials: 
0
More detailed information about the avalanche: 

Buried surface hoar existed in near and below treeline areas on N-NE-E aspects in the Bard's Bowl area. Skier triggered shooting cracks that propagated up to 200 ft occurred as this layer failed. Snowpit tests in non-wind affected areas in below treeline terrain yielded unstable results. In near treeline terrain where wind loading was occurring and wind slabs existed, skier triggered shooting cracks would propagate from flat ridgelines onto wind loaded slopes and remotely trigger wind slab avalanches that also failed on the buried surface hoar layer. A natural wind slab avalanche also occurred on a N-NE facing aspect as a result of the surface hoar layer failing. 

Photos 1-3: Natural wind slab avalanche on a near treeline wind loaded slope measuring 35-39 degrees in steepness. This slide occurred around 11:30 at the coordinates attached to this observation. It is the slide described by the characteristics noted above. 

Photos 4-6: A human triggered wind slab avalanche that also failed on the buried surface hoar layer. Surface hoar measured 2-6 mm on the bed surface of this slide. It was triggered while we were skinning on the ridge about 30 ft away from the cornice edge. The resulting cracks, avalanche, and cornice break propagated 200-300 ft away from where we initiated the cracks in low angle terrain. Photo #4 shows where the cracks started. Photo #5 shows the slide. Photo #6 shows how far the cracks and avalanche propagated. The person in the distance is standing where the cracks started and the photo is taken from where the avalanche ended. This slide occurred at 11:30 am at 38.49098, -120.00876.

Photo #7: ECTP on the buried surface hoar layer on an E facing, below treeline, non-wind-loaded slope at 8080 ft. 

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

4-6 inches of snow accumulated in this area between 7am and 1pm.