Public Observation - Close Call in Cascadilla

Location Name: 
Public Observation - Cascadilla, Flathead Range
Region: 
Flathead Range - Middle Fork Corridor
Date and time of avalanche (best estimate if unknown): 
Sat, 02/20/2016 - 15:00
Location Map: 

Red Flags: 
Recent loading by new snow, wind, or rain
Observation made by: Public
Avalanche Observations
Avalanche Type: 
Slab
Slope: 
36degrees
Trigger type: 
Snowboarder
Crown Height: 
1 ft
Aspect: 
Northwest
Weak Layer: 
Within storm snow
Avalanche Width: 
60ft.
Terrain: 
Below Treeline
Elevation: 
5 900ft.
Bed Surface: 
Old Snow
Avalanche Length: 
1 000ft.
More detailed information about the avalanche: 

Today I triggered a storm snow avalanche on the WNW trees dropping into Cascadilla from the Cascadilla-Crystal Ridge.  I ski cut across the slope and released a slide that was one foot deep on average.  It propogated immediately to my left roughly 60 feet.  I cut across the slope to the right and held onto a tree as slide continued down slope through trees.  I was able to skin back up to ridge since it all happened right below the ridge.  It was hard to tell if slide propogated to my right due to high wind and poor visibility; was potentially up to 100 feet wide if it did indeed fracture in both directions.  Avalanche slid on a bed surface that was not a crust, but certainly firm.  From Cascadilla Creek we could see that the debris ran nearly all the way to the floor of the drainage, but all of the blocks had entirely broken up since they were all soft new snow.  It resembled more of a slough than debris blocks at this point.

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate (Small trees sway)
Precipitation: 
Snow
Air temperature trend: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

We observed 40 cm of new snow in our pit from earlier in the day, which reacted with easy force.  This sat above extremely saturated snow and had a total snow depth of 340 cm where we dug (5330' NW aspect).  It contiued to snow throughout most of the day, with light wind that at times gusted to very strong on the ridgetop.  Seemed like it had recently rained on the entire trail from the highway to the upper benches in the basin.  

Activity: 
Snowboarding