Forecaster Observation - Marion/Dickey area, Flathead Range

Location Name: 
Forecaster Observation - Marion/Dickey area, Flathead Range
Flathead Range - Middle Fork Corridor
Date and time of observation: 
Thu, 03/24/2016 - 10:00
Location Map: 

Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain

Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

The first objective for today was to assess wind slab presence/absence and how reactive wind slab were from safe locations along the ridge. The second objective was to assess any storm snow instabilities. Finally, the last objective was to assess how deeper layers (like old, buried surface hoar and/or facets above the late Feb. melt-freeze crust, or facets above any of the more recent crusts (like the 3/6 RC, 3/16 RC, or 3/19 MF crust).

We observed wind loaded slopes on northwest, north, northeast, east, southeast aspects. Winds were strong throughout the day transporting a fair amount of snow. We observed both localized and shooting cracks from the ridge on these slopes. Some wind slabs adjacent to the ridge were rather stubborn when stomping on the top from the ridge, but further down the ridge produced a slab avalanche on an adjacent slope approximately 100 feet wide and 10-14 inches deep.

The avalanche was classified as SS-ASc-R3-D1.5-I. Thus, the avalanche was a soft slab avalanche intentionally triggered by a skier. It was medium size relative to the path, adn could almost bury a person, by could injure a person given the existing trees in the path. The avalanche released at the new/old snow interface. 

The fracture line depth was 10-14 inches and approximately 100 ft wide on a northeast facing slope. The slope was cross-loaded by the wind which at the time was variable, but moving generally from the south. 

We observed both localized and shooting cracks on small, wind loaded test slopes or very small rollovers along the ridge. We did not venture onto any large wind loaded slope. Cornices were very large and growing. Steer clear of these monsters.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 

March 24, 2016 - Wind Slabs in the Flathead Range

Any other comments about the observation or links to outside pages that have more info on the observation: 

Some of the avalanche information is here, but see avalanche observation for more information:

Weather Observations
Blowing Snow: 
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Strong (Whole trees in motion)
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Wind along the ridges were strong (26-38 mph) with extreme (greater than 38 mph) gusts. The wind at this location was variable and we observed active wind loading on north, northeast, east, and southeast aspects. The largest cornices were observed on east-southeast aspects. The sky was cloudy most of the day with very small and short-lived breaks in the clouds between convective cells.

Precip Rate: 
S2; moderate snowfall, 2cm/hour