Bulkley Valley - AST 2 Course Summary

Here is a summary of our AST 2 course in Smithers from Friday, Feb 9-12. We skied in the Hudson Bay and Babine Ranges. The weather was somewhat wild with sunny , warm inversions on Friday, a major westerly wind event on Saturday, a breakdown of the inversion and very light E winds at -10c at ridgelines for Sunday, and another wind event from the northwest today with -2c inversion at ridges/treeline 1600m. A change in weather was evident late PM today with the breakdown of the ridge of high pressure. We had no new precip during the course. Avalanches - great weekend for learning, with the widespread cycle on Saturday caused from the wind event. We observed natural avalanches from Size 1-3, and skier control avalanches up to size 2 in wind loaded terrain. Primarily in the Alpine and treeline elevation bands and on easterly aspects, generally in the steeper >35 deg startzones. Most of the slabs appeared to be windslabs, but a few looked to involve the deeper persistant instabilities noted in the bulletin. The snowpack is now heavily wind affected in the Alp and treeline zones, but there are protected areas still harboring some good snow. In all our test profiles, generally all at treeline in the 1550-1650m elevations we found 40cm of the past weeks settling storm snow, with an easy to moderate resistant shear, and down 85-100cm there is a complex of 2-3 crusts from January and mid December that have facets associated with them. The upper crust has some surface hoar in isolated areas, but it is laying down, and quite hard to find. In all our tests we got hard sudden collapse or planar (Drops/Pops) shears within these layers. We had no deep whumpfs on these deep layers, and the majority of whumpfs and cracking was Saturday in the fresh windslab. Our main concern during the weekend was the recent windslab in loaded features, and overhead terrain, and to large triggers, such as cornice fall on steep,large, open slopes with the deeper persistent slab.