Creme Brulee

Location Name: 
Forecaster Observation: Lake McDonald Area
Observation date: 
Friday, December 11, 2020 - 17:45

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

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Quick Observation

We went high in the Lk McDonald area to look at the interface buried on the 9th, to look at the distribution of recent wind slabs, and to see how weak the snowpack is on scoured alpine peaks. 

  • We found the custard that formed on December 8th is now a crusty creme brulee. The crust is thickest and hardest on solar aspects, on slopes steeper than about 30 degrees, and below 7,000 feet.
  • The crust is buried by a dusting of graupel below 6,500 feet. Between 6,500 and 7,500 feet, the new snow increases to about 4 inches deep and is a mix of graupel and preserved stellars. The most new snow we found above the crust was 6 inches. None of it is sticking to the crust very well.
  • The crust is almost imperceptible on northerly slopes where the new snow covers facets instead. We didn't see any buried surface hoar. 
  • Below 7,500 feet we found only minor cracking in small, shallow wind slabs. Above that elevation we saw the crown of a large slab avalanche of unknown age. We also found medium cornices and larger wind deposits below ridgelines.
  • The snowpack on high, wind-scoured slopes is shallow and very weak. It will be something to monitor as we get more snow. 
Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Glacier National Park - McDonald Lake Area
Route Description: 

To 7900'

Activity: 
Skiing
Hiking
Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
3500-5000 ft
5000-6500 ft
Above 6500 ft
Aspect(s) of observation: 
NE
E
SE
S
SW
W
Persistent Weak Layers: 
Facets or Faceted Crust
Buried
New Snow in the past 24 hours: 
0.00in.
Total Snow Depth: 
100cm
Air temperature: 
Below Freezing
Snow line: 
5100
Sky Cover: 
Mostly Cloudy (BRK)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Wednesday, December 9, 2020 - 13:00
Number of avalanches: 
1
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
Unknown
More information or comments about the avalanche: 

Date and time are very speculative.

Hide Trigger
Trigger: 
natural
Hide Terrain
Start Zone Slope Angle: 
40
Aspect: 
East
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 Width (Average width): 
150ft.
Avalanche Location: