Forecaster Observation - Outside Whitefish Mountain Resort Boundary, Southern Whitefish Range

Location Name: 
Forecaster Observation - Outside Whitefish Mountain Resort Boundary, Southern Whitefish Range
Region: 
Whitefish Range - Southern (south of Coal Creek)
Date and time of observation: 
Thu, 03/10/2016 - 11:30
Location Map: 

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

Skied into the backcountry adjacent to Whitefish Mountain Resort. Our objectives were to assess storm slab instability and hunt for surface hoar and check reactivity. While traveling along a ridgeline we were able to remotely trigger a storm slab avalanche from about 15 feet away. The slide was about 8-10 inches deep and 30 feet wide. We also observed shooting cracks and collapsing initiated from the top of a ridge. We dug snow pits on east and southeast aspects and found large grained surface hoar. This layer exists about 1.5 to 2 feet from the surface (30-50 cm) and sits atop a melt-freeze crust. 

Stability Test Results:

Pit #1: ENE aspect at 6500 feet

ECTN0 @  20 cm from the surface

ECTN1 @ 15 cm from the surface

ECTN5 @ 15 cm from surface at new/old snow interface

ECTP11 Q1/sudden collapse @ 45 cm from the surface on surface hoar

ECTN25 @ 45 cm from the surface on surface hoar

 

Pit #2: SE aspect at 6650 feet

ECTN0 @ 15 cm from the surface at new/old snow interface

ECTP 23 Q2/sudden collapse @ 50 cm from the surface on buried surface hoar

 

Snowpack photos: 
Snowpit videos (tests, etc): 

March 10, 2016 - Storm Slabs and Buried Surface Hoar, southern Whitefish Range

Weather Observations
Blowing Snow: 
No
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Light (Twigs in motion)
Precipitation: 
Mixed rain and snow
Air temperature trend: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
Activity: 
Skiing
Precip Rate: 
S -1; very light snowfall, trace to 0.5cm/hour
High Temp. (C): 
1
Low Temp. (C): 
3