Flathead walkabout

Location Name: 
Forecaster Observation - Flathead Range
Observation date: 
Thursday, November 12, 2020 - 18:00
Is this an Avalanche Observation: 
Yes
Observation made by: Forecaster

Tabs

Quick Observation

Today we went into the Flathead Range to get a baseline on the deepening snowpack. We were pleasantly surprised to find roughly 2 feet of snow on south aspects and roughly 3 feet of snow on north aspects at mid and upper elevations. 

  • New snow drifted into fresh wind slabs on north and east aspects. We found them to be small and reactive to the weight of a rider. Wind slabs were 4 to 10 inches thick, propagated up to 18 feet wide, and only ran a short distance. Although we found them to be small in size, we both discussed how dangerous it would be to get caught and dragged over the rocks and trees below. More info in the avalanche tab.
  • We found a good snowpack structure at locations where recent snow fell on bare ground. This was on southerly aspects at low and mid-elevations. 
  • We found old snow from mid October on northerly aspects at mid-elevations, and all aspects above roughly 7200'. The distribution of this old snow was variable and "pockety" due to an impressive wind event that stripped old snow down to bare rock at upper elevations (see photo). 
  • The snowpack tests we conducted all showed good stability at this time. We did find a faceted crust on a southwest and north aspect above 7000'. Though it did not fail in any snowpack tests, we will be keeping an eye on this interface as we move ahead.

We chose to ski down our up track due to timing, NRSAW, and a healthy dose of bush in our other options. The best riding we found was above roughly 5500' and in open meadowed areas. 

Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Flathead Range - Middle Fork Corridor
Activity: 
Skiing
Snowpack Details
Snowpack and Weather Details: 
Hide Terrain
Elevation of observation: 
3500-5000 ft
5000-6500 ft
Above 6500 ft
Aspect(s) of observation: 
N
NE
E
SE
S
SW
W
Red Flags: 
Shooting cracks
Blowing snow
Persistent Weak Layers: 
Facets or Faceted Crust
Buried
New Snow in the past 24 hours: 
1.00in.
Total Snow Depth: 
89 cm
More comments about the snowpack and weather: 
The vast majority of the day we were in the cloud with limited visibility. Light snowfall with gusty winds at the ridgelines. HS@low elevation=1 foot, HS@Mid elevation=2 foot, HS@Upper elevation=3 foot. Any locations where new snow fell on bare ground the snowpack is good and right side up. Where new snow fell on old snow, the structure is fair and stability is good. All crusts (or in this case a foot thick block of ice) are guilty until proven innocent. We need more information in order to prove this one innocent.
Blowing Snow: 
Moderate
Wind Speed: 
Moderate (Small trees sway)
Wind Direction: 
Southwest
Air temperature: 
Below Freezing
Sky Cover: 
Obscured by fog, etc (X)
Highest Precipitation Rate: 
Very Light Snowfall (S-1)
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Thursday, November 12, 2020 - 12:00
Number of avalanches: 
3
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
Within storm snow
More information or comments about the avalanche: 

Wind slabs were specific to leeward aspects and small in size. We did find small slabs on lee aspects where the wind hardened the surface. 

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): 
20ft.
Avalanche Width (Average width): 
18ft.
Avalanche Location: