Some areas in the west of the region near Kootenay Lake have received much more snow, and these danger rating may be too low. If your area has more than 20 cm of new snow, the danger may be considerable or higher.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Thursday
Weather Forecast
Freezing down to valley bottoms overnight with light precipitation and moderate southwest winds. A mix of convective flurries and sunny breaks on Wednesday with moderate southerly winds and freezing level climbing to 1500 metres during the day. Strong southwest winds developing Wednesday night with moderate precipitation and freezing levels up to 1600 metres. Storm continuing on Thursday with moderate precipitation and freezing levels at 1900 metres. Mostly sunny on Friday with light winds and freezing levels remaining above 1500 metres.
Avalanche Summary
Natural avalanches up to size 3.0 were reported from the west central part of the region near Kootenay Lake. The north of the region had a few reports of stubborn wind slab avalanches to size 1.5 on Monday. A few small natural avalanches and a couple of size 2.0 explosives controlled avalanches were reported on Sunday. Natural wind slabs and storm slabs up to size 2.5 were reported on Saturday.
Snowpack Summary
Close to 30 cm of new snow fell overnight in the west central part of the region near Kootenay Lake. The new storm slab was isolated to this area. The north and east of the region only received a few cm overnight combined with moderate winds. Recent strong southerly winds have developed wind slabs in the alpine and at treeline in most of the region. The 20-40 cm of recent storm snow is bonding poorly to a melt-freeze crust on previously sun-exposed slopes and lower elevation terrain, and/or a layer of surface hoar on shady and sheltered slopes at treeline elevations. The surface hoar and/or crust layer buried in mid-February is now down 50-80cm. The early January surface hoar/facet layer is typically down 70-120cm. Triggering an avalanche on this layer has become unlikely but it still has isolated potential to produce very large avalanches with a heavy trigger. In general, the lower snowpack is well settled and strong, apart from some thin snowpack areas where basal facets exist.
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.
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.