Up to 40 cm of storm snow and extreme winds initiated a natural avalanche cycle on Sunday. As temperatures cool and winds diminish, we expect natural avalanche activity to taper, but the possibility of human-triggered avalanches will remain likely.
New snow, warm temperatures, and strong south and west winds have formed surface slabs at all elevations. In exposed terrain, this problem may present as wind slabs on lee slopes. Reports of touchy cornices were also noted on Sunday.
A 40-100 cm slab sits over the Jan. 24th surface hoar layer on shady aspects, and crust/ facets on southerly slopes up into the alpine. The surface hoar has been most reactive in Yoho and Kootenay between 1600-2200m.
Local ski hills reported newly formed, widespread touchy storm slabs and wind slabs on Sunday. A combination of natural, skier-triggered, and explosive-triggered avalanches up to size 2 were observed. We suspect this natural avalanche cycle will begin to taper on Monday, but human-triggered avalanches will remain likely.
Upto 40cm of new snow has been redistributed by extreme SW winds, forming storm and windslabs at all elevations. The Jan 24 persistent layer (surface hoar/crust/facet) is down 60-100 cm and remains reactive, producing variable results in the mod to hard range. This layer is most prominent at treeline and below, but concern for southerly aspects in the alpine also exists. We expect this problem to exist for the foreseeable future.
A cool air mass will move into the forecast region behind a passing front. Light precipitation and intermittent cloud cover will continue early this week, with up to 10 cm of snow possible by Tuesday. Freezing levels will remain near valley bottom, with moderate westerly ridge winds and more precipitation expected later this week.
