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Weak layers forming on the crust
Location Name:
Forecaster Observation- Southern Whitefish Range
Observation date:
Tuesday, February 4, 2020 - 11:30
Is this an Avalanche Observation:
No
Observation made by:
Forecaster
Tabs
Quick Observation
Quick tour near WMR to document developing persistent weak layers on the snow surface.
We found small grained (1mm), angular facets developing above and below the 2/1 crust, widespread and at all elevations. The crust is thinnest and most collapsible at upper elevations (about an inch thick).
The facets are buried by an inch or two of low density stellar dendrites.
We found small grained surface hoar at low elevations. There was a cloud deck over the Swan Range today that may have provided a better moisture source for more widespread or larger grains in that range.
The snowpack was strong and stable, apart from minor sluffing in the top few inches.
Field video is
here
.
Snowpack, Avalanche, Weather Images:
Travel Details
Region:
Whitefish Range - Southern (south of Coal Creek)
Route Description:
To 6700'
Snowpack Details
Snowpack and Weather Details:
Terrain
Elevation of observation:
3500-5000 ft
5000-6500 ft
Above 6500 ft
Aspect(s) of observation:
NE
S
SW
Persistent Weak Layers:
Surface Hoar
Facets or Faceted Crust
On the surface
New Snow in the past 24 hours:
2.00in.
More comments about the snowpack and weather:
I would take a very big load for anything to collapse the 2/1 crust; likely failure interface in the near term is going to be above the crust.
Blowing Snow:
None
Wind Speed:
Light (Twigs in motion)
Wind Direction:
West
Air temperature:
Below Freezing
Snow line:
Valley
Sky Cover:
Mostly Clear (FEW)
Highest Precipitation Rate:
No Precipitation (NO)
