Claggy, with no sign of Sparklefluff

Location Name: 
Forecaster Observation - N of WMR
Observation date: 
Thursday, December 23, 2021 - 12:30

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

Tabs

Quick Observation

A quick morning tour north of WMR to check for surface hoar and wind effects. Struck out on the first; found some of the 2nd.

  • Plenty of signs that winds have been drifting snow above about 6500 feet: narrow drifts between trees, tree bomb craters well away from trees, fragile cornices, one windward slope scoured almost to ground.
  • Limited evidence that winds actually forming slabs: wind-packed snow on surface of windward slopes with < ski-length cracks with turns. Surface snow on leeward slopes not denser than snow below. Only result with dropped cornice was small, harmless slab on slope below.
  • With one exception, snow profile on northerly slope at 6650 feet looked very similar to other recent profiles. 100 cm of progressively harder snow above 12/3 MFcr (see profile diagram), with few apparent failure planes.
  • Mixed results on large column tests on rounding facets just above 12/3 crust (ECTP22; ECTX; DT21 SP). The propagating test was the only one I've seen so far this season on this layer.
  • Turns on wind-exposed slopes of about 30* produced short (< ski-length cracks) but no other signs of instability. We were unable to test steeper slopes with ski cuts.

Visibility was sub-poor. We were off the hill before cold front blew through and winds picked up.

Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Whitefish Range - Southern (south of Coal Creek)
Activity: 
Skiing
Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
Above 6500 ft
Aspect(s) of observation: 
N
S
SW
W
NW
Red Flags: 
Avalanches from the past 2 days
Blowing snow
New Snow in the past 24 hours: 
6.00in.
Total Snow Depth: 
150 cm
More comments about the snowpack and weather: 
Cloud base about 5500 ft til early afternoon, when we departed. M-S Southerly winds. Snow showers (S-1 to S1) late morning. In profile, 12/3 MFcr about same height as in other snow profiles, but more distinct layering, with dry to moist snow above and below. Surprising, given northerly aspect. Checked out one steep windward (westerly) slope and found < 35 cm of snow on bear grass. Due to poor visibility and slope angle, didn't check out further.
Blowing Snow: 
Light
Wind Speed: 
Moderate (Small trees sway)
Wind Direction: 
South
Air temperature: 
Below Freezing
Snow line: 
4500'
Sky Cover: 
Obscured by fog, etc (X)
Highest Precipitation Rate: 
Light Snowfall (S1)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Thursday, December 23, 2021 - 11:00
Number of avalanches: 
2
Avalanche Type: 
Hard Slab
Failure Plane/Weak Layer: 
Within storm snow
More information or comments about the avalanche: 

One cornice fall triggered by stomping on ridge; teeny slab below with hard debris. One older, similar slide. 

Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Cornice Fall Triggered
Hide Terrain
Start Zone Slope Angle: 
35
Aspect: 
North
Starting Elevation: 
6700'
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R2 Small
Crown Height: 
Less than 1 ft
Avalanche Length (Vertical Run): 
20ft.
Avalanche Width (Average width): 
20ft.
Avalanche Location: