Arctic Arrival

Location Name: 
BNSF Avalanche Program-Snowslip Mtn. GNP
Observation date: 
Friday, February 8, 2019 - 21:45
Is this an Avalanche Observation: 
No
Observation made by: Public

Tabs

Quick Observation
  • Toured up the Infinity/Shed 9 ridge on the south face of Snowslip Mtn. and traversed over to the top of the Shed 7 W path. Descended Shed 7 W back to the Hwy.
  • Objective was to investigate the avalanche that ran in the Infinity path last Tuesday (2/5). The crown was mostly filled back in with new snow and we could not safely reach the location of the avalanche. But dug a pit and profile about 50 yards east of the site.
  • Also wanted assess the most recent wind loading.
  • The Arctic front arrived a bit earlier than expected. By late morning temperatures were dropping and winds had clocked from the W to the NE and were increasing in speed.
  • Very light snowfall most of the day with overcast skies in the AM and broken skies by early afternoon.
  • Moderate NE winds were lightly loading westerly aspects at all elevations.
  • Only about 1-2 inches of new snow in the past 24 hours.
  • The NE winds were forming thin new slabs primarily on S-SW-W aspects at all elevations today.
  • These new slabs were actually more reactive at low-mid elevations. Ski cut one very small slab, 6” thick x 12’ wide at about 5000 feet.
  • We dug a snowpit and conducted a full snow profile on a south aspect at 6200 feet elevation on the ridge immediately to the east of the Infinity path.
  • Still not certain what the weak layer/failure plane was for the Feb 5 Infinity avalanche. But we suspect a layer of surface hoar that formed in mid-January and was buried about 2 feet below the surface at the pit location.
  • Cornices in Infinity, Shed 9, and Shed 7 were eroding back into the slope by the wind.
  • No avalanche activity observed since Tuesday February 5th.
Snowpack, Avalanche, Weather Images: 
Avalanche Details
Avalanche Details: 
Date and Time of Avalanche: 
Friday, February 8, 2019 - 21:45
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
New/old snow interface
More information or comments about the avalanche: 
  • The NE winds were forming thin new slabs primarily on S-SW-W aspects at all elevations today.
  • These new slabs were actually more reactive at low-mid elevations. Ski cut one very small slab, 6” thick x 12’ wide at about 5000 feet.
Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Intentionally Triggered
Hide Terrain
Aspect: 
South
Starting Elevation: 
5000
Hide Size
Destructive Size: 
D1 Relatively harmless to people.
Relative Size: 
R1 Very Small
Crown Height: 
Less than 1 ft
Avalanche Width (Average width): 
12ft.
Avalanche Location: