Regions
Kootenay Boundary.
The snowpack is touchy and primed for human-triggered avalanches.Don't let the improving weather lure you into high risk scenarios.
Confidence
Fair - Timing of incoming weather systems is uncertain
Weather Forecast
High pressure building in the North will be responsible for a cooler and dryer NW flow. Some unstable disturbances are embedded in this flow, bringing scattered cloud and light precipitation. Models disagree with timing and precipitation amounts on Sunday.Saturday: Cloudy with sunny periods. Alpine temperatures near -12.0. Light northerly ridgetop winds.Sunday: Cloudy with some light snow up to 5 cm. Alpine temperatures near -16.0. Ridgetop winds light from the SW.Monday: Sunny. Alpine temperatures near -11.0. Ridgetop winds blowing light from the north.
Avalanche Summary
Natural slab avalanche activity up to size 2.5 on all aspects and elevations. Remote triggering and long fracture propagations continue and a skier remote size 3 (50 m away) was reported. Endless settlements and whumphing experienced while traveling on low angle terrain. Low elevation cut-blocks are releasing naturally at the persistent weak interface.
Snowpack Summary
Moderate to strong SW winds has loaded leeward and cross-loaded exposed slopes. There is over a metre of recent storm snow that is sitting on a weak layer that is a mixture of facets, surface hoar, melt-freeze crusts and any combination of these. The weak layer is widespread at all elevations and aspects and continued whumpfing and avalanche activity is reported. The storm slab continues to settle and become more cohesive allowing for longer fracture propagations and remote triggering. This persistent weak layer is expected to be a concern for some time; at least through the weekend.
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.
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.