Regions
Kootenay Boundary.
Weather Forecast
Wednesday: Mostly clear with freezing levels in valley bottoms and moderate northwesterly winds. Thursday: Increasing clouds and freezing levels as high as 1300m, with moderate southwesterly winds. Friday: Light snowfall with freezing levels as high as 1300m, and moderate westerly winds.
Avalanche Summary
Recent reports include isolated human triggered Size 1 thin soft wind slab avalanches running on large surface hoar, on south through east facing treeline slopes.
Snowpack Summary
10-15 cm low density snow sits above a weak layer of large surface hoar and/or facets, with and associated crust on sun-exposed slopes. A sufficiently cohesive slab for fracture propagation and avalanche release has formed on wind-loaded slopes, but for the most part, the slab is neither deep nor stiff enough for large avalanches. We typically see dangerous slab avalanches start to occur when the depth to the weak layer reaches approximately 40cm. Check out the Forecaster's Blog link below for a discussion on incremental loading of potentially persistent weak layers. The mid and lower snowpack are generally well-settled and strong. Basal facets lurk in shallow snowpack areas, but we've received no recent reports of associated instabilities.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.