Regions
Kootenay Boundary.
Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain on Saturday
Weather Forecast
Thursday: Mostly clear with freezing levels rising as high as 1300m and moderate to strong westerly winds. Friday: A mix of sun and cloud, but dry, with freezing as high as 1500m and moderate to strong westerly winds. Saturday: Light to moderate snowfall expected primarily on the western side of the ranges. Freezing levels expected to remain around 1500m, and strong southwesterly winds.
Avalanche Summary
Recent avalanche activity has been limited to isolated minor sluffing on steep shady slopes.
Snowpack Summary
Light amounts of new snow has covered new surface hoar overlying 10-15 cm low density snow sitting on another weak layer of large surface hoar and/or facets, with an associated crust on sun-exposed slopes. The uppermost surface hoar may not yet be fully protected from the elements that can destroy it, such as sun, wind, and especially rain, but at this point it seems to be just as widespread but smaller than the deeper layer. 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. 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, but recent reports suggest basal facets create a deep persistent slab problem that deserves caution in shallow snowpack areas on planar rocky slopes.
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.