Purcells

Fair - Freezing levels are uncertain on Monday

A firmly embedded ridge of high pressure will continue to dominate the region bringing clear skies and light southerly winds throughout the forecast period. An inversion with above freezing alpine temperatures will persist on Sunday, but will give way to a gradual cooling pattern forecast for Monday and Tuesday.

Since the recent warming, numerous large and destructive avalanches (to size 3.5) were reported in the region. Most of the avalanches were specific to south-facing alpine features. Some of these avalanches were initiated by cornice fall. Others were loose, wet avalanches that, in some cases, stepped down to basal weaknesses.

The big story is the recent weather. Sun exposed slopes are becoming moist and cornices are weakening due to solar radiation and increased alpine temperatures.Wind slabs are also likely to be found on exposed areas at treeline, and into the alpine and storm slabs can be found at all elevations. They both seem to be settling out quickly, but still show sensitivity to rider triggers; especially on steeper slopes and convex rolls. Below this sits a fairly well settled mid-pack. There are, however, a few exceptions. The Jan. 13th SH/FC combo has been reactive. As well, the mid December facet/surface hoar layer is buried approx. 80 cm on the east side and 200+ cm on the west side and has been more reactive in the Purcells than any other region. There are also basal facets at the ground which will continue to remain a concern, especially in the thin snowpack parts of the region. In addition to more obvious cornice failure and loose wet snow movement due to current warming, any of the aforementioned weaknesses could become reactive producing large and destructive slab avalanches. Snowpack depths at 2000m sit near 2m deep.