Weak basal snow Peak 6996'

Location Name: 
Forecaster Observation - Peak 6996, GNP
Observation date: 
Sunday, December 23, 2018 - 15:30
Is this an Avalanche Observation: 
No
Observation made by: Forecaster

Tabs

Quick Observation

Traveled to the eastern end of our advisory area to collect baseline snow structure data. 

  • Snow depth at the trailhead (4500') was 4-6" with ~ 40" at 6800'.
  • Instabilities limited to one collapse (whoomphing) when I stepped off my skis at an upper elevation snow pit.
  • At upper elevations, the lower foot of the snowpack consisted of weak faceted snow. Pushing a ski pole into the pack easily identified this weak layer.
  • Failure and propagation, with moderate force, occurred in the facet layer during stability tests.
Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Glacier National Park - Southern Lewis Range
Route Description: 

Up the standard south ridge route to Peak 6996'.

Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
5000-6500 ft
Above 6500 ft
Aspect(s) of observation: 
NE
E
SE
Red Flags: 
Collapsing / whumpfing noises
Blowing snow
Persistent Weak Layers: 
Facets or Faceted Crust
Buried
New Snow in the past 24 hours: 
2.00in.
Total Snow Depth: 
40"
More comments about the snowpack and weather: 
Snowpit @ 6800' on an east aspect: Snow depth was 40" with the top 12" recent snow (F to 4F) with a 16" strong (1F) mid pack resting on a 12" layer of facets (4F). Repeated propagation occurred at the facet layer with moderate force (ECTP 12). Snowpit @ 6800' on a southeast aspect: Snow depth was 35" with the lower 14" consisting of a crust sandwiched by facets. Propagation occurred in the facets above the crust repeatedly with moderate force (ECTP 13).
Blowing Snow: 
Moderate
Wind Speed: 
Moderate (Small trees sway)
Wind Direction: 
West
Air temperature: 
Below Freezing
Snow line: 
2000'
Sky Cover: 
Overcast (OVC)
Highest Precipitation Rate: 
Moderate Snowfall (S2)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Sunday, December 23, 2018 - 19:30
More information or comments about the avalanche: