North Rockies - Mackenzie - Pine Pass -Hassler -Silver Sands Flight

Feb 22,2012 Observations from an overflight through these areas of the North Rockies Forecast Zone today. Most noteable observation was the occurring and recent Avalanche Cycle. This was most pronounced in the Pine Pass corridor, likely due to heavier recent snowfall available for wind transport. Mod -Strong West winds all day loading into E-NE Aspects. Saw numerous slabs out in the Size 2-2.5 range, and several Size 3 slides in the head of Rolston Creek running full path, and also on the NE side of the Murray Range ( across from Powder King). All crowns were pulling out in the middle 1/2 of the start zones due to the intense wind transport, with impressive propogations. Avg depth were in the 40-60cm range, likely failing on the Feb 16 ish Facet layer under the recent wind loaded storm snow. The Hasler area had a much lower snowpack in general, and the area has seen a lot of wind this year, as evidenced by all West aspects scoured to ground in many places. Not as much avalanche activity here, as through the pine pass, as there is not a lot of snow available for transport. The Silver Sands area was similiar to Hassler, noted isolated windslabs out to size 2. I would be quite careful of punching up into any windloaded start zones, or dropping into anything for the next sev days, until these windslabs gain strength. Cheers; Sean Fraser ACMG Ski Guide CAA Professional Member