Felt like winter

Location Name: 
Forecaster Observation - WMR sidecountry
Observation date: 
Saturday, December 28, 2019 - 20:45

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

Tabs

Quick Observation

Toured into the sidecountry east of WMR to look for recently-formed weak layers under the most recent snow, wind-drifted snow, and the lingering Persistent Slab problem.

  • Very light snow through the afternoon, with 1-5" of very low-density snow over the past two days. 
  • The previous snow surfaces include 1-2" melt-freeze crusts on sunny slopes (SE-S-SW aspects) and small, near-surface facets. Did not find any surface hoar in hand pits in the terrain we surveyed. 
  • We triggered a few small, harmless sluffs on slopes steeper than 35 degrees. These didn't run far or entrain much snow. 
  • We found no signs of drifted snow n the generally sheltered terrain where we toured. 
  • The 11/19 crusts/ facets did not fail in a large column test, but did fail (break) in a deep tap test (most of slab removed). The slab above this combination is 1-finger hard, and the grains above the crust are rounding. 
  • We did not find any well-developed facted layers above the crust. Some small faceted grains exist just below the new snow, and make for difficult skinning. They are small and don't show much angularity. 

With no signs of instability and few obvious weak layers in the snowpack, we felt comfortable skiing open, planar slopes up to 35 degrees, along with short steep pitches with consequences.

 

 

Snowpack, Avalanche, Weather Images: 
Snowpack, Avalanche, Weather Videos: 

20191228 chicken Bones

Travel Details
Region: 
Whitefish Range - Southern (south of Coal Creek)
Route Description: 

East of WMR, 5600-6650'. Slopes up to 38 degrees. 

Activity: 
Skiing
Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
5000-6500 ft
Above 6500 ft
Aspect(s) of observation: 
E
SE
W
Persistent Weak Layers: 
Facets or Faceted Crust
Buried
New Snow in the past 24 hours: 
4.00in.
Total Snow Depth: 
135 cm
More comments about the snowpack and weather: 
Calm to light winds and no blowing snow or freshly-formed drifts. S-1 most of afternoon. Large crystals, very low density.
Blowing Snow: 
None
Wind Speed: 
Calm (No air motion)
Air temperature: 
Below Freezing
Sky Cover: 
Overcast (OVC)
Highest Precipitation Rate: 
Very Light Snowfall (S-1)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Saturday, December 28, 2019 - 13:00
Number of avalanches: 
2
Avalanche Type: 
Loose Dry/ Sluff
Failure Plane/Weak Layer: 
New/old snow interface
More information or comments about the avalanche: 

Triggered with ski cuts on above steep convexities. Only released on slopes > 35*.

Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Intentionally Triggered
Hide Terrain
Start Zone Slope Angle: 
37
Aspect: 
Southeast
Starting Elevation: 
6100
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R1 Very Small
Avalanche Length (Vertical Run): 
40ft.
Avalanche Width (Average width): 
10ft.
Avalanche Location: 
Date and Time of Avalanche: 
Saturday, December 28, 2019 - 14:45
Number of avalanches: 
3
Avalanche Type: 
Loose Dry/ Sluff
Failure Plane/Weak Layer: 
New/old snow interface
More information or comments about the avalanche: 

Triggered with ski cuts; ran with some speed and entrained some snow.

Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Intentionally Triggered
Hide Terrain
Start Zone Slope Angle: 
38
Aspect: 
West
Starting Elevation: 
6100
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R1 Very Small
Avalanche Length (Vertical Run): 
75ft.
Avalanche Width (Average width): 
20ft.
Avalanche Location: