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:

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.

Trigger

Trigger:

natural

Terrain

Starting Elevation:

above-treeline

Size

Destructive Size:

D2 Could bury, injure, or kill a person.

Relative Size:

R2 Small

Avalanche Location:

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Loose dry and Persistent slab structure at Red Meadow

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

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Loose dry and Persistent slab structure at Red Meadow

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

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