Regions
Kootenay Boundary.
Avalanche danger is variable across the region due to local snowfall and wind patterns. Danger ratings may be too high for areas with limited recent snowfall.
Confidence
Poor - Due to variable snowpack conditions
Weather Forecast
Friday night/Saturday: Moderate to strong SW winds. Moderate snowfall overnight, easing to light on Saturday. Alpine temperature around -6.Sunday: Moderate to strong NW winds. Light to moderate snow, starting late in the day. Alpine temperature around -4.Monday: Light to moderate W winds. Light to moderate snow. Alpine temperature around -8.
Avalanche Summary
Several size 1 soft slabs and loose snow avalanches were observed on NE-NW aspects on Friday. Explosives testing also led to several size 1-2.5 slabs which failed on a crust on SE to SW aspects over the last couple of days.
Snowpack Summary
At the time of writing, 10-30 cm of snow overlies weak interfaces buried in mid-February (mainly surface hoar/ sun crust layers). By Saturday morning, there may be a deeper storm slab above these interfaces, with the potential for wide propagations and surprisingly large avalanches. Where winds have shifted the snow into slabs in the lee of terrain breaks, the size and likelihood of avalanches will be greatest. I feel that the snowpack is approaching a tipping point in this region, and may follow the pattern observed further north last week (numerous skier-triggered avalanches, including a few surprising remote-triggers on the mid-Feb weaknesses). Exactly when and where a cohesive storm slab will develop will vary locally according to the distribution of buried weaknesses and the amount of snowfall and wind.Older snowpack weaknesses buried in the upper snowpack (Feb 4th and Jan 23 surface hoar/facet/sun crust layers) are still being tracked by professionals but have not been reactive recently. The lower snowpack is generally well settled.
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.