Regions
Kootenay Boundary.
More snow and wind overnight will keep avalanche danger elevated on Tuesday. Be careful as you move into wind-affected terrain.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Tonight and Tuesday: 10-15 cm of snow overnight followed by cooling and clearing during the day. The freezing level peaks near 1600-1800 m overnight and lowers to 1400-1500 m during the day. Ridge winds are strong from the SW easing to moderate during the day. Wednesday: Showers or flurries with sunny breaks. The freezing level rises to 1800-2000 m. Winds are light and variable. Thursday: Periods of snow. The freezing level drops to 1200 m and winds increase to moderate or strong from the SW.
Avalanche Summary
Numerous size 1-2 explosive or skier controlled avalanches were reported throughout the region on Sunday. One size 2 accidentally triggered slab avalanche was reported in the Northern Rossland Range on Saturday. This avalanche was about 40 cm deep and was triggered on a NE aspect. One person was partially buried but escaped unharmed.
Snowpack Summary
30-50 cm of recent storm snow sits on a supportive crust at and below treeline, a breakable crust on south-facing slopes in the alpine, buried surface hoar in sheltered terrain, or old wind affected surfaces. Moderate south-southwest winds have created fresh dense wind slabs on exposed leeward slopes. A few buried surface hoar layers exist in the top 100 cm in drier areas on the west side of the region. In other areas the notable early January surface hoar layer is 80-130 cm deep and poses a low probability/ high consequence threat. It should remain on your radar, especially in thin snowpack areas and during periods of significant warming or rapid loading.
Problems
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.