Touchy storm slabs reactive to human triggers. Conservative decision making will be CRITICAL to playing safe in the mountains this weekend.
Confidence
Moderate - Forecast snowfall amounts are uncertain
Weather Forecast
Saturday night: 15-20 cm new snow/ Strong, southwest winds/ Freezing level 250m.Sunday: 5-10 cm new snow/ Moderate, southwest winds/ Freezing level 250m.Monday: 0-5 cm new snow/ Light southwest winds/ Freezing level sea level.Tuesday: Mostly cloudy with flurries/ Light, southwest winds/ Freezing level sea level.
Avalanche Summary
On Saturday, numerous skier triggered avalanches up to size to 2 were reported near Whistler. Human triggered avalanches are expected to remain very likely throughout the weekend.
Snowpack Summary
30-40 cm of new snow has buried a wide variety of old snow surfaces including stiff wind slab or wind effected snow at upper elevations, sun crust on steep southerly slopes, surface hoar and surface facets in sheltered locations. An additional 15-20 cm is expected by Sunday morning, bringing storm totals to 40-60 cm. The mid-January interface (facets) is buried approximately 60-100 cm down and recent snowpack tests have shown hard, yet sudden planar results. The mid and lower snowpack is generally well settled (strong). However, there remain a number of facet and crust layers that are currently dormant but will require monitoring with additional loading.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.