Cold air to the Rescue after a significant avalanche cycle

Location Name: 
Forecaster Observation- Rescue Creek, Flathead Range
Observation date: 
Friday, February 9, 2018 - 15:30

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

Location

Tabs

Quick Observation

Big cycle yesterday: 

  • More than a dozen natural storm slabs, up to D2.5, mostly above 6000’.
  • One D3 persistent slab that ran at 5600’ triggered by rain.
  • Numerous wet loose avalanches, up to D2, below 6000’
  • Two D3 debris piles in valley bottoms, and 2 deep slab crowns that failed on the Thanksgiving crust near the ground, couldn’t see their runout but likely D3s.

Snowpack: 3” to 5” low density snow over a solid rain crust (5”-7” thick) up to at least 6000’ made for a trustworthy snowpack.  Shallow sluffing was our only concern at mid and low elevations. No obs from above 6000’, where the snowpack looks to have dodged the rain and is more dangerous and complex. 

 

Snowpack, Avalanche, Weather Images: 
Snowpack, Avalanche, Weather Videos: 

February 9, 2018. Cold air to the Rescue, Flathead Range

Travel Details
Region: 
Flathead Range - Middle Fork Corridor
Route Description: 

Rescue Creek to Wahoo saddle up 6000’

Activity: 
Skiing
Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
3500-5000 ft
5000-6500 ft
Aspect(s) of observation: 
NW
Persistent Weak Layers: 
Not observed
New Snow in the past 24 hours: 
5.00in.
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Thursday, February 8, 2018 - 10:30
Avalanche Type: 
Hard Slab
Failure Plane/Weak Layer: 
Old snow
More information or comments about the avalanche: 

I had views of 2 deep slab crowns and 1 debris pile that was probably a deep slab. Crowns were relatively narrow. Looks like they ran on Thanksgiving crust. 

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
Northwest
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D3 - Could destroy a car, a wood house, or snap trees
Crown Height: 
10 ft
Avalanche Width (Average width): 
150ft.
Avalanche Location: 
Date and Time of Avalanche: 
Thursday, February 8, 2018 - 10:30
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
Unknown
More information or comments about the avalanche: 

Storm slabs/wind slabs

Hide Trigger
Trigger: 
natural
Hide Terrain
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small
Crown Height: 
2 ft
Avalanche Length (Vertical Run): 
1500ft.
Avalanche Width (Average width): 
200ft.
Avalanche Location: 
Date and Time of Avalanche: 
Thursday, February 8, 2018 - 10:30
Avalanche Type: 
Hard Slab
Failure Plane/Weak Layer: 
Old snow
More information or comments about the avalanche: 

Based on crown depth/ elevation, I estimate this failed on one of our mid January rain crusts. Debris looked pretty wet. 

Hide Trigger
Trigger: 
natural
Hide Terrain
Aspect: 
Northeast
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D3 - Could destroy a car, a wood house, or snap trees
Crown Height: 
3 ft
Avalanche Length (Vertical Run): 
1500ft.
Avalanche Width (Average width): 
800ft.
Avalanche Location: 
Date and Time of Avalanche: 
Thursday, February 8, 2018 - 10:45
Avalanche Type: 
Wet Loose
More information or comments about the avalanche: 

Mid and lower elevations. 

Hide Trigger
Trigger: 
natural
Hide Terrain
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D2 Could bury, injure, or kill a person.
Relative Size: 
R2 Small
Avalanche Location: