Regions
Kootenay Boundary.
Tricky conditions are expected and conservative route selection is critical
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Saturday
Weather Forecast
Saturday: Mainly cloudy with light snow and strong southwesterly winds in the afternoon. Total accumulation of up to 5 cm and freezing levels remaining in valley bottoms. Sunday: Mainly cloudy with 5-10cm of snow, strong southwesterly winds and freezing levels in valley bottoms. Monday: a mix of sun and cloud with lingering light flurries. warming temperatures but freezing levels expected to stay below 1500m, and light to moderate southwesterly winds.
Avalanche Summary
Reports from Thursday include numerous explosive and skier controlled storm slab avalanches up to Size 2, with up to 60cm thick slabs but generally low density. Sun-exposure in some areas also initiated a loose dry natural avalanche cycle with surface sluffs up to Size 2 on steep south facing slopes.
Snowpack Summary
Weaknesses exist within the 30-40cm of recent storm snow (or possibly up to 50cm in some areas), which is also bonding poorly to buried surface hoar sitting on sun crust on south aspects or facets in shaded areas. Wind and warm temperatures have promoted slab development in many areas, however in some sheltered areas there may still be insufficient storm snow settlement and cohesion for storm slab conditions. About 70-90 cm below the surface, you might find a rain crust from mid-December which co-exists with facets in some areas. Recent snowpack tests suggest that it could still be capable of producing human triggered avalanches. The snowpack below this layer is generally strong and well-settled.
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.