Skin Wax

Location Name: 
Swan Range
Observation date: 
Monday, December 21, 2020 - 18:15
Is this an Avalanche Observation: 
Yes
Observation made by: Forecaster

Location

Tabs

Quick Observation

Today we went into the Swan Range to get rained on and feel the wind on our faces. Aside from observing the onset of the next round of precipitation, we wanted to assess wind slab sensitivity and dig around to see if we can find a persistent slab structure. 

  • Generally, we found 12 to 15 inches of new and recent snow. Overnight accumulations appeared to be 2 to 4 inches. 
  • We triggered multiple small wind slabs on leeward and windward aspects. It was obvious that there were two generations of wind slabs. Today's were reactive, yesterdays were stubborn.
  • Elevations up to roughly 6000' held a crust/facet/crust combination. This felt more problematic than higher up where the 12/9 MF crust does not exist. 
  • We were surprised to find a degrading and faceting snowpack on a ENE aspect at roughly 6700 feet. The thick melt freeze crust from early November that sits near the ground showed evidence of faceting. It was less of a block of ice, and more of a mixed bag of sugar and burnt cookies. 
  • On our descent, at roughly 6000 feet, we began to feel the snow surface become moist. Soon after we noticed rain falling. 

We went out today with terrain steeper than roughly 35 degrees with consequential runouts closed. This opened up a world of worry free riding.

Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Swan Range - West Side (Flathead Valley access)
Activity: 
Skiing
Snowmobiling
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
S
SW
Red Flags: 
Shooting cracks
Rain on snow
Blowing snow
Persistent Weak Layers: 
Facets or Faceted Crust
Buried
New Snow in the past 24 hours: 
8.00in.
Total Snow Depth: 
125 cm
More comments about the snowpack and weather: 
I will add a pit profile tomorrow. Summary: Below 6000' has roughly a foot of new and recent snow sitting on a crust/facet/crust. Below this, we found a good basal structure on a NW aspect. On a SW aspect it appeared to be shallower, and more faceted. 6700' ENE aspect we found a degrading/faceting snowpack. A very hard, thin freezing rain crust made snowpit tests feel unreliable.
Blowing Snow: 
Moderate
Wind Speed: 
Moderate (Small trees sway)
Wind Direction: 
Southwest
Air temperature: 
Below Freezing
Snow line: 
5500
Sky Cover: 
Obscured by fog, etc (X)
Highest Precipitation Rate: 
Light Snowfall (S1)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Monday, December 21, 2020 - 12:00
Number of avalanches: 
2
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
Within storm snow
Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Intentionally Triggered
Hide Terrain
Start Zone Slope Angle: 
38
Aspect: 
North
Starting Elevation: 
near-treeline
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R1 Very Small
Crown Height: 
Less than 1 ft
Avalanche Length (Vertical Run): 
50ft.
Avalanche Width (Average width): 
10ft.
Avalanche Location: 
Date and Time of Avalanche: 
Monday, December 21, 2020 - 12:00
Number of avalanches: 
2
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
Within storm snow
Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Intentionally Triggered
Hide Terrain
Start Zone Slope Angle: 
38
Aspect: 
Northwest
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R1 Very Small
Crown Height: 
Less than 1 ft
Avalanche Length (Vertical Run): 
50ft.
Avalanche Width (Average width): 
15ft.
Avalanche Location: