Regions
Kootenay Boundary.
The storm may have ended, but "whumpfing" in the snowpack indicates that deeply buried layers may still be reactive with potential for large avalanches.
Confidence
Poor - Due to the number of field observations
Weather Forecast
On Friday, expect generally overcast skies, light southwest winds and freezing levels at about 1500m. Throughout Saturday and Sunday, a dry ridge of high pressure is forecast to develop bringing clearing skies, light northwest winds and freezing levels closer to 1000m.
Avalanche Summary
Although observations have been limited, I suspect loose wet avalanche activity has been fairly widespread with the wet weather. Rain or loading from snow may also spark destructive avalanche activity on persistent weaknesses which exist near the base of the snowpack. If you have any avalanche observations, please share them on our new Mountain Information Network. For more details, go to: https://avalanche.ca/blogs/VIYBuScAAJdbdqPz/m-i-n-intro
Snowpack Summary
Rain has likely saturated the upper snowpack in most areas. The extent of saturation will depend on elevation and the amount of rain that fell. The rain-soaked snow may exist as a hard crust in many areas with forecast cooling. At upper elevations, precipitation may have fallen as moist snow, and may be adding load and cohesion to a storm slab which overlies a weak layer of facets, surface hoar, a hard rain crust or a combination thereof.Near the base of the snowpack is a crust/facet combination which is a concern at higher elevations in many parts of the region. This destructive layer continues to produce whumpfing, and may see a "wake-up" with the load from rain or snow.
Problems
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.
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.