Regions
Kootenay Boundary.
Avalanche danger is expected to increase on the weekend.
Confidence
Fair - Intensity of incoming weather is uncertain on Saturday
Weather Forecast
Friday: Light snowfall with 2-5cm of accumulation, moderate southwesterly winds, and freezing levels around 1300m. Saturday: 5-15cm of new snow expected with moderate to strong westerly winds and freezing levels rising as high as 1600m late in the day. Sunday: Trace amounts of new snow expected with freezing levels again reaching 1600m 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
Surface hoar is is growing on the snow surface again and some areas have three different surface hoar layers buried in the top 15cm, but the deepest layer is largest and most widespread across the region. 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 attention 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.