Professional Observation - John F. Stevens Canyon, southern Glacier National Park

Location Name: 
Professional Observation - John F. Stevens Canyon, southern Glacier National Park
Region: 
Flathead Range/Glacier National Park - John F. Stevens Canyon
Date and time of observation: 
Tue, 01/26/2016 - 12:00
Location Map: 

Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

Toured up the Shed 11/10.7 ridge to the starting zone elevation of Shed 11.  Excavated a full profile in a test slope near the SZ of Shed 11 and also conducted an ECT stability test near the flank of the Shed 10.7 feeder path.

Skiing conditions were good on ascent and descent at low elevations (below 5,200 feet) due good snow cover. Upper elevations were more difficult to travel due to deep windslab formation.

  • Windloading/ crossloading occurring on easterly and northeasterly aspects.
  • Deep windslab development on SE and E aspects above 5,500 feet elevation.
  • Isolated shooting cracks initiated under single skier weight.
  • One audible collapse noted at 6200’ elevation on a SE aspect and just above a convex roll.
  • No cornice or avalanche activity observed.
  • Conducted a full profile on a 33 degree, S-SE aspect at approximately 6,330 feet.
  • HS at profile location was 115 cm. Main focus of snow profile data at this location was an interface located 50 cm from the snowpack surface.  Interface consisted of small facets and decomposing surface hoar resting on a well-established melt-freeze crust. Stability tests on this layer interface resulted in ECTP15 and ECTP16 Q1- failures.
  • No significant temperature gradient in the snowpack at the Shed 11 test slope location.  0 degree C snowpack T from 60 cm to the ground.
  • Also conducted an ECT stability test on the flank of the Shed 10.7 feeder path.  This location was on a SE aspect at 6200 feet elevation and 32 degree slope. Snowpack depth was 133 cm and an ECT stability test resulted in propagation on the same layer interface of concern in the Shed 11 test slope. ECTP13 Q1-
  • No avalanche activity observed. 
Snowpit videos (tests, etc): 

1 26 16 Shed 11 ECT

Any other comments about the observation or links to outside pages that have more info on the observation: 

BNSF AVALANCHE SAFETY FIELD OBSERVATIONS SUBMITTED TO FLATHEAD AVALANCHE CENTER AND GLACIER NATIONAL PARK ARE BEING PROVIDEDED IN ACCORDANCE WITH THE TERMS AND CONDITIONS SPECIFIED GLACIER NATIONAL PARK SPECIAL USE PERMIT.  

 

Weather Observations
More detailed information about the weather: 

Overcast and broken skies, moderate westerly winds, and no precipitation throughout the day. Air temperatures were in low thirties at Canyon floor elevations and in the mid to upper twenties at elevations above 5,200 feet. Active windloading occurring on easterly aspects throughout the day.

Activity: 
Skiing