Public Observation - Marion Lake, Flathead Range

Location Name: 
Public Observation - Marion Lake, Flathead Range
Region: 
Flathead Range - Middle Fork Corridor
Date and time of observation: 
Wed, 04/05/2017 - 11:55
Location Map: 

Red Flags: 
Recent avalanche activity
Recent loading by new snow, wind, or rain
Rapid warming
Obvious avalanche path
Observation made by: Public
Snowpit Observations
More detailed information about the snowpack: 
  • On Monday 3/3 at noon on a SE-facing slope at 5500'  below peak 7852 there was 4 inches of new snow on a wet crust that was supportive on skis, but boot penetration was above the knee into wet mush.  That crust became firmer as I climbed and wrapped around on to shadier aspects.   Above 7000' on a West aspect above Almeda Lake the new cohesionless snow on the almost mirror-smooth crust made for interesting skinning.  Kicking steps worked better.
  • NE-facing ridge of peak 7798 had impressive cornices.
  • Observed no obvious signs of instability, and ski cutting wind-loaded test slopes produced no results beyond  sluffing of top few cm's.
  • Dug a hasty profile Tuesday morning at 7200' just below the ridge on a 35 degree NE-facing slope, looking for recent wind slabs and how they were bonded to the most recent crust.  Found the crust at 80cm from surface.  Clearly, there had been some fairly recent wind-loading.
  • 1 cm surface hoar on surface.  15 cm of F hardness new snow sat on a thin layer of small facets.
  • Generally 4 F from approx. 15cm to approx. 35cm down.
  • Generally 1 F from approx. 35cm down to the most recent crust.
  • Recent crust was approx. 15cm thick and  pencil hardness.
  • CT 17 Q3 x 2 @ 35cm
  • ECTN 19 @ 35cm, ECTN 23 @35cm
  • I observed no full propagation in my one-person ECT s with normal loading steps, but I did get full propagation above the crust at 80 cm with a solid kick, twice.
  • Avoided areas below corniced slopes, and found a bit less of a recently wind-loaded slab to ski on.  The thinner slab was not reactive to hand tests or ski cuts on 40 degree slopes.
  • Skiing was excellent down to about 6500', where the crust was noticable below 15 cm of new snow. 
  • Observed small natural point releases on steep, rocky SE-facing slopes, and triggered small sluffs on 40 degree NE-facing slopes.
  • Overnight winds mostly filled in previous day's tracks.
  • Picked conservative terrain on my route out and found good crust cruising on a lighly timbered  NE-facing ridges from about 6000' to about 4600', where the crust was barely supportive on skis at 1pm, and there was no trace of Monday's snow.
  • On my route out I found that upper elevation westerly and southerly slopes had a firm re-frozen surface with no ski penetration, while shaded slopes still had uncrusted powder and/or windslab.
Snowpit or crown profile photo or graph: 
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: 
None
More detailed information about the weather: 
  • Toured up the South Dickey drainage on Monday 3/3.  At noon at 5500' it was 26 F, winds were calm and snow was falling at about two inches an hour. 
  • Snowfall tapered off in the p.m., skies cleared and the low Tuesday morning was 11 F at 7200'.
  • Tuesday was clear day above Marion Lake, though Mount Adams and Cameawait remained in the clouds until late afternoon.  Winds were light from the West and Southwest.  Temperature remained below freezing in the shade above 6500'.
  • Winds picked up to moderate from the SW on Tuesday night and continued Wednesday morning. 
  • Wednesday the skies were overcast with a ceiling well above ridgetop level.  At 6:00 am it was 20 F at 7200' and at noon it was 32 F at 6800' on Essex Mountain with very light snow falling.

 

 

 

 

 

Activity: 
Skiing
Precip Rate: 
S -1; very light snowfall, trace to 0.5cm/hour
High Temp. (C): 
0
Low Temp. (C): 
-11