Regions
Kootenay Boundary.
Be on the lookout for wind slabs in the alpine. Avoid likely trigger spots such as shallow, rocky, wind affected areas.
Weather Forecast
The Pacific low continues to intensify off the coast bringing precipitation and strong winds to the Interior regions. Friday: Cloudy, freezing levels 1200 m, alpine temperatures near -5.0, snow amounts 5-10 cm, ridgetop winds strong from the southwest.Saturday: Cloudy freezing levels valley bottom, snow amounts 7-15 cm, ridgetop winds moderate-strong from the southwest.Sunday: Some model disagreement, however; unsettled conditions may bring snow amounts 5-10 cm with moderate to gusting winds from the northwest.
Avalanche Summary
No recent avalanche observations have been submitted. Moderate SW winds and 10-20 mm forecast through Saturday could build new wind slabs on leeward slopes and behind terrain features. Pay attention to changing avalanche conditions especially at upper elevations.
Snowpack Summary
Early season snowpack observations are still very limited in the region, but the threshold for avalanches has been exceeded at treeline and in the alpine. Most areas below treeline are below threshold for avalanches with only the smoothest open slopes beginning to reach threshold. The snowpack depth is reported to be 140-180cm at treeline and above. Remote weather data and recent Mountain Information Network posts from the Kootenay Pass area suggest wind slabs may exist on lee slopes just below ridge crest; however, we are unsure of the reactivity or the distribution of the problem throughout the region. This problem may develop further with forecast winds and 5-10 mm over the next couple of days. A thick crust from mid-November is down around 70 cm and recent reports suggest the layer is generally well bonded to the adjacent snow. Below this crust layer the snowpack is reported to be moist or wet to the ground at treeline elevation.
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.