Avalanche burial during mitigation work at WMR

Location Name: 
Whitefish Mountain Resort
Observation date: 
Thursday, December 13, 2018 - 22:15

Is this an Avalanche Observation: 
Yes
Observation made by: Public

Tabs

Quick Observation

Continuing to see snow and wind on the Big and wanted to give you an update on an incident that happened today.  We had a patroller buried in a slide while ski cutting in a small slide path in Fault 1 off of Inspiration, east aspect directly off the groomed ski run (currently closed.)  Crown averaged 30-40 cm and is 95 cm at its deepest.  Patroller was entering the path on a ski cut and triggered the slide from the left edge, where the crown was 20 cm.  He was then caught and carried for approx. 100 feet downhill and was buried with only his hand and the back of his helmet showing. Patroller 2 was spotting from above on the groomed surface and was able to perform an effective, fast companion rescue and the buried patroller was unharmed.

The avalanche was approximately 75 ft wide and ran 100ft downhill and terminated at the treeline.  I classify the slide as HS-AS-D1.5-R4-O.  I investigated the site (unfortunately, much of my snow study kit was not with me) and found the slide ran on facets above a very subtle crust  (likely the November rain crust?) Did a quick compression test at the crown and got CT12 with a Q1 shear.  At the deepest, the avalanche stepped down through the crust and ran on facets above the ground.

We've been doing extensive control work in the area over the last week in anticipation of storms on the weak snowpack, but this is a great example of the little underestimated pockets that can surprise you.  Glad it turned out ok.

Snowpack, Avalanche, Weather Images: 
Travel Details
Route Description: 
Snowpack Details
Snowpack and Weather Details: 
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Thursday, December 13, 2018 - 10:15
Avalanche Type: 
Hard Slab
Failure Plane/Weak Layer: 
Old snow
More information or comments about the avalanche: 
Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Intentionally Triggered
Hide Terrain
Aspect: 
East
Hide Size
Destructive Size: 
D1.5
Relative Size: 
R4 Large
Crown Height: 
3 ft
Avalanche Length (Vertical Run): 
100ft.
Avalanche Width (Average width): 
75ft.
Hide People Involved
Number of people caught: 
1
Number of partial burials: 
1