South Rockies

Good

A Pacific frontal system is expected to bring light snow accumulations starting later tonight into Wednesday. The weather pattern for the rest of the forecast period looks to be fairly benign.Wednesday: Snow amounts near 5 cm, with ridgetop winds 30 km/hr from the West and alpine temperatures near -11.Thursday: Light flurries with ridgetop winds blowing light from the West and alpine temperatures near -12.Friday: Cloudy with few sunny breaks, ridgetop winds light from the West and alpine temperatures near -10.

On Sunday afternoon skiers triggered a size 3.0 slab avalanche from the ridgeline off Mt. Fernie. The initial trigger was a smaller wind slab which then stepped down to a deeply buried rain crust. There were no human involvements. For further details, please visit the Incident report here:  https://avalanche.ca/cac/library/incident-report-database/view. I suspect the storm slabs will still be touchy to rider triggers, especially in wind effected areas where the storm slab tends to be stiffer.

The average storm slab depth is approximately 20 to 50 cm, and may be sensitive to rider triggers; especially in areas with wind effect on lee slopes and behind terrain features (spines, gullies, ridgelines). Two crusts have been identified in the snowpack: one close to the ground that formed in early November and one around 90-140 cm below the surface, which formed in early December. Recent snowpack tests done on the December crust from the Harvey Pass Riding Area showed a moderate compression test failure, with a sudden collapse characteristic. The testing done on that layer showed inconsistent results. Recent compression and deep tap tests done in the Lizard Range have shown hard results. This layer may be difficult to trigger, especially in deeper snowpack areas. However, if triggered, a large and destructive avalanche would occur. The mid pack is generally well settled throughout the region.