Professional Observation - BNSF Avalanche Safety Field Observations

Location Name: 
Professional Observation - Shed 11/10.7, John F. Stevens Canyon, Flathead Range
Region: 
Flathead Range/Glacier National Park - John F. Stevens Canyon
Date and time of observation: 
Thu, 12/22/2016 - 12:00
Location Map: 

Red Flags: 
Recent avalanche activity
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: 
  • Snowpack encountered on the tour was quite variable. Still very punchy with no supportable base below 5500 feet. Otherwise found a mix of supportable wind slabs and then a thin wind crust which was not supportable. And then sometimes deep (1+ m) unconsolidated powder. Arduous skinning and sporty skiing.
  • Had one audible collapse on windslab pocket at about 5200 feet.
  • Hasty pit at 6400’ on a 32 degree slope, S aspect. 85 cm HS. Upper 35 cm basically a stack of wind slabs, 4F to 1F hardness. Bottom 50 cm was a layer of facets (4F-) to the ground. ECTP 26 on top of this layer.
  • While skiing down the Shed 10.7/11 ridge noticed several cracks where some wind slabs just started to move downslope off the ridge crest, but then arrested in place. Likely occurred sometime on Tue or Wed. This was on skier’s left, and the western flank of Shed 10.7 path. Some of these cracks were up to 10 cm wide and close to 1 m deep (photo).
  • Otherwise no recent avalanches observed. But I suspect avalanches did occur, only the crowns were quickly hidden by the steady supply of wind-transported snow earlier in the week.
Snowpack photos: 
Any other comments about the observation or links to outside pages that have more info on the observation: 

Toured up the Shed 11/10.7 ridge to the weather station just above the top of the Shed 11 avalanche path. Spent some time maintaining weather station and then dug a hasty pit in the very upper reaches of the Shed 11 start zone. Descended the same route.

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
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Light (Twigs in motion)
Air temperature trend: 
Static
Wind Direction: 
Southwest
More detailed information about the weather: 

Broken skies, calm or light southwest winds, and air temperatures in the upper 20s F at elevations above 6000 feet. No precipitation. A pleasant day to work on the weather station

Activity: 
Skiing