Professional Observation - BNSF Avalanche Safety, John F Stevens Canyon, Glacier Park

Location Name: 
Professional Observation - BNSF Avalanche Safety, John F. Stevens Canyon, Glacier Park
Region: 
Flathead Range/Glacier National Park - John F. Stevens Canyon
Date and time of observation: 
Mon, 03/13/2017 - 12:00
Location Map: 


Observation made by: Public
Snowpit Observations
More detailed information about the snowpack: 

Began the tour at the Burnout avalanche path and the climbed the SE ridge of Snowslip Mountain above the Shed 4D, Shed 5, and Shed 7 East avalanche paths. Dug a snowpit near the Shed 7 weather station in the very upper reaches of the Shed 7 East path (6300 feet, ESE aspect, 25° slope. Climbed a little higher on the ridge to about 6500 feet elevation in order to better view the cornice fall in Shed 7 West. Descended the same route.

  • Snowpack on the tour was quite variable. Below 5500 feet encountered a spring-like snowpack with a thin, breakable melt-freeze crust over wet snow on the surface in the morning which turned into wet, mashed potato snow on the ski down in the afternoon. Above 5500 feet found a mix of wind slabs (sometimes supportable on skis) along with sticky powder on the sunny slopes, and cold, dry powder on shaded slopes. Skin wax was helpful.
  • While the winds were steady at moderate speeds with occasional strong gusts, by early afternoon the actual wind-loading had tapered off as the warm temperatures and sunshine began to melt and stiffen the surface snow.
  • Wind slabs encountered on the tour were very stubborn. No releases, collapses, or shooting cracks observed.
  • HS at the snow pit location was 260 cm (0 cm at the ground). The Feb. 10 crust was down 90 cm from the surface. A thin layer of facets was seated on top of the crust, CT 25 SP result in a compression test on this layer, but no fractures with an extended column test. Also observed fractures but no propagation in the upper 30 cm of the snowpack, some of which occurred just below the mid-Feb crust.
  • Snow was getting quite punchy by early afternoon below 5500 feet elevation. There is plenty of wet loose snow for entrainment at the mid to low elevations.
  • A large chunk of the cornice in Shed 7 West broke out recently (photos attached). This triggered a very small wind slab immediately below the ridge crest. Associated debris ran only a few hundred feet.
  • A few small wet loose sluffs ran in Burnout and Shed 4D.
  • Otherwise no other new (overnight and today) avalanche activity observed by 1400 when I left the Program Area.
Snowpit or crown profile photo or graph: 
Snowpack photos: 
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 PROVIDED IN ACCORDANCE WITH THE TERMS AND CONDITIONS SPECIFIED IN THE GLACIER NATIONAL PARK SPECIAL USE PERMIT.   

THESE OBSERVATIONS REPRESENT SITE SPECIFIC INFORMATION INTENDED FOR THE BNSF AVALANCHE SAFETY PROGRAM AND IN NO WAY ARE TO BE CONSTRUED AS A PUBLIC/ RECREATION AVALANCHE FORECAST.  

Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Moderate (Small trees sway)
Precipitation: 
None
Air temperature trend: 
Warming
Wind Direction: 
Southwest
More detailed information about the weather: 

In the morning skies were broken with no precipitation and periods of sunshine. By early afternoon skies were overcast with very light snow above 5500 feet and very light rain below this elevation. Moderate to strong west-southwest winds at all elevations all day. Air temperatures in the high 30s to low 40s °F at the Canyon floor and just above freezing at elevations above 6000 feet.

Activity: 
Skiing
High Temp. (C): 
1
Low Temp. (C): 
0