Windy in JFS Canyon

Location Name: 
BNSF Avalanche Program-Snowslip Mtn. GNP
Observation date: 
Wednesday, January 2, 2019 - 18:00
Is this an Avalanche Observation: 
Yes
Observation made by: Public

Tabs

Quick Observation
  • Travelled up the south face of Snowslip Mtn. via the Shed7/6 ridge to the Shed 7 weather station then continued up the ridge to 7000 feet and the Snowslip weather station.
  • Objective was to assess new snowfall amounts along with the recent wind,-loading. Also needed to keep investigating the snowpack structure, specifically the persistent weak layer(s) near the bottom of the snowpack.
  • Descended via Shed 7 West.
  • Overcast skies, with intermittent S-1 snowfall and moderate to strong west winds near the ridge crests. Air temperatures were in the 20s °F above 6000 feet elevation for most of the day.
  • The snowpack is finally deep enough to ski from the rail grade. Our manual weather/snowpack measurement stations in the Canyon both show about 14 inches of snow on the ground. Essex has 23 inches.
  • Above 5500 feet elevation moderate to strong westerly winds were actively loading east aspects. Still we observed few signs of instability other than a few minor shooting cracks running only about 2-4 feet.
  • The cornices above Shed 7 West that were almost fully eroded earlier this week by east winds are now re-building due to the recent snow and steady westerly winds.
  • We dug a snowpit in the upper reaches of Shed 7 West at 6650 feet elevation on as easterly aspect (pit profile below). The poor snowpack structure remains with the December facets present near the ground underneath a firm mid pack of 1F hardness. The first Extended Column Test resulted in ECTX, the second in ECTN16 on a density change between layers about 16 inches down. 
  • One small (D1.5) slab avalanche triggered by a falling cornice ran about 700 vertical feet from the top of Shed 7 West. This debris terminated in the upper 1/3rd of the avalanche path.
  • No other avalanche activity observed.
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: 
Wednesday, January 2, 2019 - 08:00
Avalanche Type: 
Soft Slab
Failure Plane/Weak Layer: 
New/old snow interface
Hide Trigger
Trigger: 
skier
Trigger Modifier: 
Cornice Fall Triggered
Hide Terrain
Aspect: 
East
Starting Elevation: 
above-treeline
Hide Size
Destructive Size: 
D1.5
Avalanche Length (Vertical Run): 
700ft.