Professional Observation - Green Mountain, Whitefish Range

Location Name: 
Professional Observation - Green Mountain, Whitefish Range
Region: 
Whitefish Range - Northern (north of Coal Creek)
Date and time of avalanche (best estimate if unknown): 
Sat, 02/11/2017 - 15:30
Location Map: 

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: Public
Avalanche Observations
Avalanche Type: 
Dry
Slab
Slope: 
34degrees
Trigger type: 
Skier
Crown Height: 
3 ft
Aspect: 
East
Weak Layer: 
Old snow
Avalanche Width: 
200ft.
Terrain: 
Near Treeline
Elevation: 
7 700ft.
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: 

This avalanche was remotely triggered from roughly 100 yards away as we ascended the NE ridge of Green Mountain.  It ran on a facet layer buried ~60cm deep, but stepped down in places an additional 20+cms.  The slab fractured blocks back onto the low angle ridge and propogated cracks upslope an additional 50 yards.  HS-ASr-R2-D2.

There was additional evidence of similar natural slab activity throughout the Ten Lakes area. We observed multiple natural cliff-base slab avalanches from the previous day or two (assuming they happened during the storm) beginning to refill with wind deposited snow.  It was confirming to see after having very reactive stability tests earlier in the day on a similar aspect and elevation (see snowpack observation).

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate (Small trees sway)
Precipitation: 
None
Air temperature trend: 
Cooling
Wind Direction: 
West
Accumulation rate: 
None
Activity: 
Skiing