Professional Observation - Wind slab development, southern Whitefish Range

Location Name: 
Professional Observation - Wind slab development, southern Whitefish Range
Region: 
Whitefish Range - Southern (south of Coal Creek)
Date and time of observation: 
Mon, 12/19/2016 - 11:45
Location Map: 

Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

We toured in the backcountry adjacent to Whitefish Mountain Resort near Ghoulie's Point above Canyon Creek in the southern Whitefish Range today.  While we were in the area the winds were transporting snow and began to form soft wind slabs on leeward slopes.  

We were able to trigger a small, shallow (10-12 inch) avalanche just off the ridge (see attached photo). We also observed shooting cracks ahead of our skis.  This all occurred on the leeward side of the ridge.  When traveling/skiing on the southern slopes (less wind affected) we did not observe any signs of instability.

We dug a pit on a north facing slope with results of ECTP11 @ 45 cm down (ECTP = full propagation across the column).  The aforementioned windslab that failed appeared to fracture on top of a layer of small facets.  We did not observe fractures within the snowpack below that.  

Snowpack photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light (Twigs in motion)
Precipitation: 
Snow
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
Activity: 
Snowboarding