Forecaster Observation - Avalanche above Lamoose Lake, Swan Range

Location Name: 
Forecaster Observation - Lamoose Lake/Lost Johnny, Swan Range
Region: 
Swan Range - East Side (Hungry Horse Reservoir access)
Date and time of avalanche (best estimate if unknown): 
Sat, 04/02/2016 - 14:00
Location Map: 

Red Flags: 
Recent avalanche activity
Rapid warming
Obvious avalanche path
Observation made by: Forecaster
Avalanche Observations
Avalanche Type: 
Dry
Slab
Slope: 
40degrees
Trigger type: 
Natural
Crown Height: 
3 ft
Aspect: 
Northeast
Weak Layer: 
Old snow
Avalanche Width: 
200ft.
Terrain: 
Above Treeline
Elevation: 
6 800ft.
Bed Surface: 
Old Snow
Avalanche Length: 
400ft.
Number of people caught: 
0
Number of partial burials: 
0
Number of full burials: 
0
More detailed information about the avalanche: 

Cornice fall that likely occured earlier in the morning triggered what we suspect was an older wind slab. We rode over to get a closer look and while we were there at about 2:00 another piece of cornice broke off and the slab propagated farther across the slope.

Avalanche Photos: 
Avalanche observation video: 

April 2, 2016 - Cornice Fall

Weather Observations
Blowing Snow: 
No
Cloud Cover: 
50% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Light (Twigs in motion)
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
None
Activity: 
Snowmobiling