Regions
Kootenay Boundary.
Fresh storm slabs will form on a variety of surfaces and be primed for human triggers. Start in simple terrain without consequence to assess the bond of the new snow and avoid large avalanche paths.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
THURSDAY NIGHT: Cloudy with flurries; 1-3 cm. / Light, southwesterly winds / Low -3/ Freezing level below valley bottom.FRIDAY: Snow, 15-25 cm. / Moderate, southwesterly winds / High -2 C / Freezing level valley bottom. SATURDAY: Cloudy with sunny periods / Light, southerly winds / High -2 C / below valley bottom.SUNDAY: Cloudy with flurries; 3-5 cm. / Light, northwesterly winds / High-5 C / Freezing level below valley bottom.
Avalanche Summary
No avalanches were reported in the region on Wednesday. However, fresh storm slabs reactive to human triggers will form on Friday.
Snowpack Summary
There is currently a wide variety of snow surfaces. Sun crusts on south aspects to mountaintops, some of which have small surface hoar(weak, feathery crystals) growing on top, which is a particularly nasty combination. Most exposed alpine areas have been heavily wind effected. 5-10 mm surface hoar has been widespread in areas that are protected from sun and wind.Around 20 to 40 cm down, expect to find a crust on south aspects and feathery surface hoar crystals in sheltered and shaded areas. The surface hoar is currently the primary layer of concern and may be most reactive at treeline elevations on shady aspects. However, no recent avalanches have been reported on this layer.The remainder of the snowpack is generally well-settled and strong in most locations.
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.