Regions
Kootenay Boundary.
Check out this great video blog post which describes conditions in the Nelson area: http://backcountryskiingcanada.com/forums/view/safety-talk/avalanche-conditions-report-video-1
Weather Forecast
A dry ridge of high pressure will dominate the region for the period. Valley cloud should develop for most days, although generally clear skies are expected at higher elevations. Winds are forecast to remain light from the northwest, while freezing levels should hover at (or near) valley bottom.
Avalanche Summary
On Saturday, skiers triggered numerous persistent slab avalanches to size 2 in the north of the region, in some cases remotely from a distance of 10m. With the stable weather pattern, recent storm instabilities should become much less reactive; however, I would expect ongoing skier-triggered avalanche activity on the December persistent weak layers.
Snowpack Summary
A dusting of low-density snow overlies well-developed surface hoar which sits above a melt-freeze crust. The crust is reported to exist on all aspects below about 1900m, and on steep solar aspects at higher elevations. Stubborn wind slabs are likely in exposed alpine and treeline terrain. The main snowpack concern is a buried surface hoar layer (down 60-120 cm), which is sitting on a hard rain crust in some places. This widespread persistent weakness, which formed in December, exists at all elevation bands and remains a concern for triggering.
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.