Cold Smoke in the Banana Belt

Braved the arctic intrusion for some chilly wiggles in the seldom slashed North Fork of the Flathead. Traveled up Hay Creek to ski an unnamed peak two days in a row, 2/3 and 2/4.

Sunday 2/4:

• Lightly snowing all day. 1.5" accumulated in the valley floor and 3"+ above 5400'
• Lots of gusting wind in Polebridge during the night prior, but surprisingly little wind effect noted during our outing. And mostly calm winds all day
• Distinct snow surface changes noted during our ascent;
  • Below 5400'- thin (1-2") cohesionless storm slab resting on top of stout crust from warm weather/rain on Saturday.
  • Between 5400' and 5600'- stout crust becomes less stout. Ski penetration gradually increasing. Slightly improved interface with the new snow.
  • Between 5800' and 6200'- stout crust vanishes. Ski penetration increases. Storm slab thickens to 7-9".
• We saw the first burst of precip Saturday evening (2/2), which came as rain on the valley floor, tapering off at dark and not picking up again until about 5am post arctic intrusion.
• We believe that the snow/freezing rain line was near 5400' Saturday evening, and above 5800', we were observing the combined precip from Saturday evening's dense snow and sunday's arctic dust. (combined 7-9" storm slab).
• We skied sheltered terrain SSE facing. 

Monday:

• Traveled back up Hay Creek to discover what -56 degree wind chills feel like... The forecast was a little over zealous. We saw -14 degrees at 9am and calm winds.
• Snow tapered off around dark Saturday evening and blustery winds blew through the valley floor during the night again.
• In the morning, it was snowing S3 for about 40 minutes between 9:30 and 10am. Other than that burst, it was snowing trace amounts throughout the day with moments of clearing skies. Overall about 2.5" in the valley floor since Sunday morning and 4"+ above 5400'
• Again, we were surprised to see very little wind effect.
• Toured in the same terrain today. At 3:03pm, we dug a pit on an east facing slope at 5879 to assess and document the 1/17 persistent slab (buried surface hoar) problem.
• The surface hoar layer was easily distinguished and well preserved on this slope.
• Individual surface hoar grains were large (1cm) and the layer was relatively close to the surface. 46cm (18") below the surface in my pit.
• Stability Tests proved that this was the most problematic layer at this elevation. CT12 Q1 and ECTP17 Q1. In our ECT, the 46cm slab propagated cleanly and fast across the entire block and popped off the column into the pit.
• We skied the same SSE facing slopes as yesterday.
• The only instabilities we observed were below 5600 where the light cohesionless snow (2-4") is forming a shallow slab that very easily releases loose dry activity on top of the stout crust from warming weather before the arctic intrusion. This could become more problematic if the temps remain cold and these slabs thicken on certain terrain features at mid elevations.