Loose dry and Persistent slab structure at Red Meadow

Location Name: 
Forecaster Observation - Red Meadow Lake, Whitefish Range
Observation date: 
Friday, December 22, 2017 - 15:30
Is this an Avalanche Observation: 
Yes
Observation made by: Forecaster

Tabs

Quick Observation
  • Dozens of small, natural loose dry sluffs on steep road cuts and river banks, suggesting it would have been easy to trigger a sluff today.
  • We did minimal off-road traveling but saw no other obvious signs of instability, except for a few naturals that ran earlier in the week, D2 in size.
  • Persistent slab structure consists of ~80cm of recent snow over a thin rain crust capping our December dry spell facets.  See profile for details.  The slab did not propagate in our test pit near the lake.  It seems the crust needs additional loading before collapses/failures become widespread, but the structure is poor and I wouldn't rule out human triggering.  
Snowpack, Avalanche, Weather Images: 
Snowpack, Avalanche, Weather Videos: 

December 22, 2017. Persistent Slab Structure in the Whitefish Range

Travel Details
Region: 
Whitefish Range - Northern (north of Coal Creek)
Route Description: 

Up the east side of Red Meadow Road to the lakes at 5,500 feet. Returned via the road. 

Activity: 
Snowmobiling
Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
5000-6500 ft
Red Flags: 
More than a foot of new snow or heavy snowfall rates (>1"/hr)
Persistent Weak Layers: 
Buried
New Snow in the past 24 hours: 
12.00in.
Total Snow Depth: 
160cm
More comments about the snowpack and weather: 
See profile
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Tuesday, December 19, 2017 - 22:30
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
Unknown
More information or comments about the avalanche: 

Slides on both northerly and southerly aspects. 

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
Avalanche Location: