Regions
Kootenay Boundary.
Confidence
Fair - Intensity of incoming weather is uncertain
Weather Forecast
Tuesday: Cloudy, with precipitation building late in the day as a surface low approaches. Winds should be westerly 50-70km/h and freezing levels may climb to 1000m.Wednesday: The surface low should bring moderate to locally heavy snowfalls. Freezing levels may reach 1500m as the low advances with southwest winds reaching 60km/h.Thursday: The low should pass leaving occasional flurries and eventually sunny breaks. Winds turn northeasterly and diminish to 20km/h.
Avalanche Summary
Isolated windslabs in lee terrain to size 1.0 and continued sluffing in steep terrain to size 1.0.
Snowpack Summary
Up to 15cm of low density new snow has fallen recently. Moderate south/southwest winds have redistributed this new snow into small windslabs in immediate lee features in the alpine and exposed treeline.The January 4th interface consists predominantly of loose facets up to 30cm deep. In isolated locations (sheltered treeline and below treeline) surface hoar up to 12mm is present. There is a 1-3cm sun crust on steep south and west facing terrain. Above this interface is another surface hoar layer, creating a reactive sandwich of weak crystals. The storm snow is bonding poorly to this interface.The midpack is well bonded and strong. The November 28 surface hoar is still being found in isolated, sheltered below treeline locations buried 95-120cm. The deep crust/facet combo from early November still exists and concern remains (although unlikely) for triggering from a shallow spot.
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.
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.