Professional Observation - John F. Stevens Canyon

Location Name: 
Professional Observation - John F. Stevens Canyon
Region: 
Flathead Range/Glacier National Park - John F. Stevens Canyon
Date and time of observation: 
Mon, 01/09/2017 - 12:00
Location Map: 

Red Flags: 
Recent loading by new snow, wind, or rain
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 
  • In the past 24 hours, approximately seven inches (7”) of relatively dense (120 Kg/m3) new snow accumulation had been deposited on lighter density old snow interface. 
  • This condition created an “upside-down” snowpack where the more recently deposited snow with greater density was fracturing and nearly sliding on the underlying lower density snow. 
  • Newly deposited snow observed was very soft (fist hardness) and lacked structure for slab formation.
  • Only very localized propagation in newly deposited snow was observed throughout the day.
  • Older snow layers beneath newly deposited snow continue to be completely faceted and unconsolidated at elevations below 5200 feet.
  • Above 5200 feet, pockets of totally unconsolidated, faceted snow exist but there is also areas that have had significant windloading. 
  • Substantial cornice development has occurred on easterly aspects above 5,600 feet elevation.
  • Full profile at 6000 feet elevation. 280 slope with SE aspect.  Impressive windloading at this location.  Snowpack depth was 205 cm. Structure consist of increasingly hard layers positioned atop 50 cm of 4Fand F+ hardness facets.  Significant T gradient in a majority of the snowpack at this location.
  • No ECTP results in stability tests. CT2 and CT5 (Q3) observed in upper 30 cm of profile. CT17 Q3 observed 42 cm from snowpack surface at this location.
  • No avalanche activity observed.
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: 

Toured up the trimline of the Burnout avalanche path to the east ridgeline of Snowslip Mountain. Conducted a full profile and stability tests at just to the right of the Shed 5 starting zone.  Descended 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
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Moderate (Small trees sway)
Precipitation: 
Snow
Air temperature trend: 
Warming
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 
  • Overcast skies, light to moderate snowfall with intermittent heavy snowfall episodes.  Approximately 4” of new snowfall occurred through the day.
  • Air temperatures fluctuated significantly Depending on location during the morning hours. 
  • As an example, air temperature at Devil Creek, on the Canyon floor, was 80 F.  At Essex, where we had just left, the air temperature was 210 F.  Later in the afternoon the Devil Creek air temperature had impressively increased to 300 F.
  • Also, important to note, when we began our field observations in the morning, overrunning was occurring in the Program Area with warm air streaming over the previously entrenched cold air. 
  • This overrunning condition was responsible, impressive snowfall rates and for significantly warmer air temperatures at Program Area upper elevations than what existed at lower elevations during the same time period.
  • Winds were westerly and light to moderate in strength. 
  • Wind strength increased throughout the day. 
  • Active windloading was occurring on easterly aspects during the afternoon hours at all elevations.  
Activity: 
Skiing
Precip Rate: 
S2; moderate snowfall, 2cm/hour
High Temp. (C): 
25