Small wind slabs and one big collapse

Location Name: 
BNSF Avalanche Safety - Snowslip Mtn. GNP
Observation date: 
Tuesday, January 5, 2021 - 23:00
Is this an Avalanche Observation: 
Yes
Observation made by: Public

Location

Tabs

Quick Observation
  • Toured up the Shed 6/7 ridge to the Shed 7 weather station at 6100’ elevation.
  • Descended the Shed 5 area.
  • Objectives were to assess the recent wind-loading and snowpack stability with close attention to the Dec. 9th and 22nd crusts and check on the weather station.
  • No avalanche activity observed aside from a mini wind slab (D1) ski-triggered on a test slope on a SE aspect and 5600’ elevation (Test Slope 2 - photo). Debris terminated well above the rail.
  • Overnight snowfall totals above 6000’ elevation were about 3-4”.
  • Several generations of wind slabs above 5000’ from the consistent westerly winds over the past week. Some of these were reactive to ski cuts, while others were unreactive.
  • Shed 7 West cornice has grown considerably over the past week.
  • Breakable crust on the snowpack surface from the Canyon floor up to about 4800’.
  • Hasty pit dug at 5500’ on a SE aspect and a wind-loaded location. HS=43” with the Dec 22nd crust buried 20” down and the Dec 9th crust 30” down from the surface. No propagation and ECTN28 on the Dec 22nd crust.  
  • One audile collapse in an area known as Test Slope 2 (5600’, SE aspect) after a few forceful ski stomps. Same location as the small avalanche mentioned above.
  • Mostly overcast skies with an occasional break for a ray or two of sunshine. No precipitation with light westerly winds.
  • Daytime high air temperatures warmed to about freezing on the Canyon Floor and up to the mid-20s/high teens °F at elevations above 6000’.
Snowpack, Avalanche, Weather Images: 
Travel Details
Region: 
Flathead Range/Glacier National Park - John F. Stevens Canyon
Activity: 
Skiing
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Tuesday, January 5, 2021 - 13:30
Number of avalanches: 
1
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
New/old snow interface
Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Intentionally Triggered
Hide Terrain
Aspect: 
Southeast
Starting Elevation: 
5600
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R1 Very Small
Crown Height: 
Less than 1 ft
Avalanche Length (Vertical Run): 
100ft.
Avalanche Width (Average width): 
25ft.
Avalanche Location: