Avalanche Forecast

Good

Tonight and Wednesday: Moderate snowfall with 10-20cm likely overnight, and 5-10cm possible on Wednesday. The freezing level (FL) drops overnight to 800-1000m. Strong westerly winds overnight shifting to moderate-strong from the northwest on Wednesday. Thursday: Mainly dry under a weak ridge of high pressure. FL 600-800m. Friday: Light to moderate snowfall - 5-15cm with the greatest amounts likely in the south. FL at valley bottom. Winds should be moderate from the southwest.

There are numerous reports of natural and easily triggered soft slab avalanches up to size 2.5 at all elevations. Most of these avalanches were 30-40cm deep and released on the Feb. 16 surface hoar layers, with some releasing on the Feb. 8 surface hoar/ facet/ sun crust interface. A few avalanches were triggered from a distance. An avalanche cycle is likely on Wednesday and it may be possible to trigger avalanches in surprisingly low angle terrain or from a distance.

Moderate west-southwest winds are creating new wind slabs in exposed alpine and treeline terrain. Up to 50cm of new snow now sits on the February 16th Surface Hoar layer and is slowly settling into a cohesive slab. The February 8th weakness is now down 60-80cm. This layer is a combination of weak layers: In most locations it marks a widespread surface hoar layer. On steep south & west facing aspects a sun crust that formed during the drought was also buried on Feb. 8th. This crust likely has a bit of faceting below it too, meaning that most terrain in the region has a weak layer 40-60cm under the snow surface. Below this problematic interface a well settled mid pack is in place. The exception is the eastern and southern parts of the region where deeper weaknesses and basal facets may still be a factor. In these areas, a low-probability/high-consequence condition exists. It should be noted that large cornices remain widespread throughout the region.