Blackcomb backcountry

Quick report

There's been some near-misses and sadly some fatalities in adjacent areas so I thought it would be good to call out one observed phenomena from yesterday and from the previous few days. This is a bit more detail than I'd ordinarily call out particularly since all obs are from hasty assessments. Take it all for what it's worth. There was significant variable reverse windloading from some NW and NE winds. That means that slopes that are usually not windloaded (S facing sunny slopes) got a significant amount of snow. But not all S facing sunny slopes got snow; so you may be lulled into a false sense of security. For example crossing from the Guides Notch traversing S facing slopes there was 10- 15 cms of low-density snow in the early morning. As soon as I crested a ridge there was 2-5cms of snow overlaying rocks. Then crossing another ridge past a rib that acted as a shield, the windloading resulted in 20 - 30cms of low-density. That's a significant amount of variability in a 300m traverse on essentially the same aspect. By the afternoon the surface of that same snow had a melt-freeze pencil thin crust. There were some naturals off S and SE slopes from the lower flanks of Phalanx in the Whistler area that looked like they were triggered by snow rollers possibly initiated by solar absorption from rock walls. This was in the Warrior, Stairmaster and a variety of also SE and ESE facing couloirs off Phalanx. The SE traverse onto Corona had not YET acquired enough heat to melt-freeze but I felt that the pure S facing slopes were starting to acquire heat and possibly merit caution (just a visual obs across the valley towards Wedge as the snow surface was acquiring the sheen of MF). Even crossing the SE traverse merely pole probing you could feel the snow texture and density changing in the space of the short 100m where you're a bit exposed heading to Corona from the Spearhead Glacier. A reasonable inference is that this was from the reverse windloading.