Avalanches in JFS Canyon

Location Name: 
BNSF Avalanche Safety - JFS Canyon
Observation date: 
Friday, December 20, 2019 - 15:00
Is this an Avalanche Observation: 
Yes
Observation made by: Public

Location

Tabs

Quick Observation
  • Snowed about 1 inch yesterday in Essex before precip turned to rain in the midle of the night. Looks lik terrain above 6000 ft picked up 3-6 in of snow. Snow/rain line was creeping up towards 6000 ft. by the afternoon.
  • Some small wet loose avalanches (D1-1.5) on steep cutbanks near the Canyon floor.
  • Larger (D2) soft slabs in Path 1163 on the south face of Running Rabbit Mtn. More info under the Avalanche Details tab.
  • Even larger (D3?) hard slab that appeared to fail on facets near the base of the snowpack on the N face of Mt. Furlong in Path known as Broken Bridge. More info under the Avalanche Details tab.
Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Flathead Range/Glacier National Park - John F. Stevens Canyon
Route Description: 

Road observations

Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Friday, December 20, 2019 - 08:15
Number of avalanches: 
3
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
New/old snow interface
More information or comments about the avalanche: 

Multiple crowns, estimated ranging 30-150 ft. wide near the top of Path 1163. Appeared to be storm/wind slabs with debris entraining some wet snow on the way down terminating about 2/3rds path. Observed around 1400 and suspect these ran last night/early this morning, Dec 20. Westerly winds were actively re-loading this face at time of observation.

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
South
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small
Crown Height: 
1 ft
Avalanche Length (Vertical Run): 
2000ft.
Avalanche Width (Average width): 
100ft.
Avalanche Location: 
Date and Time of Avalanche: 
Friday, December 20, 2019 - 05:15
Number of avalanches: 
1
Avalanche Type: 
Hard Slab
Failure Plane/Weak Layer: 
Old snow
More information or comments about the avalanche: 

I turned around after checking out Path 1163 and saw this nasty thing on the N face of Furlong. Unfortunately my view of the avalanche was very limited and I'm guesstimating on the slab dimensions. I could not see the debris or runout at all. But from the photo it appears a cornice fall likely triggered the slab below on the cliffs then this debris triggered the big slab lower on the slope. Hard saying but that crown could be 4+ thick in places? Looks like failure was on some old facets near the base of the pack. Obviously a wind-loaded slope that made for a thicker slab. And it had been re-loading for while before I took this picture, so thinking this avalanche ran last night/early morning.
 

Hide Trigger
Trigger: 
natural
Trigger Modifier: 
Cornice Fall Triggered
Hide Terrain
Aspect: 
North
Starting Elevation: 
7300 feet
Hide Size
Destructive Size: 
D3 - Could destroy a car, a wood house, or snap trees
Relative Size: 
R3 Medium
Crown Height: 
3 ft
Avalanche Width (Average width): 
500ft.
Avalanche Location: