Regions
Kootenay Boundary.
New snow and wind are increasing the avalanche danger. Storm slabs may release naturally or be triggered by light additional loads like skiers/riders.
Confidence
Poor - Due to the number of field observations
Weather Forecast
Overnight and Monday: 15-30 cm of snow overnight as the cold arctic air from the North meets the warm moist Pacific air crossing from the West. The mountain passes in the South of the region may see higher snowfall amounts. Freezing levels dropping to valley bottoms and winds becoming moderate from the Northeast by Monday afternoon.Tuesday: Cold and dry with light Northerly winds.Wednesday: Sunny, dry and cold.
Avalanche Summary
The new storm snow is expected to release naturally or with light additional loads like skiers. Areas that have a deeply buried early season crust may experience a cycle of large avalanches due to the added load of the storm snow.
Snowpack Summary
New storm slabs are developing above recently buried weak layers of surface hoar on North aspects and melt/freeze crusts on solar aspects. The new snow may not bond well to these old weak surface layers. There are some reports of a deeply buried early season crust that formed in October. We do not know the extent of this layer with respect to aspect and areas within the region. In other regions of the interior mountains, this layer is more likely to be found in the high alpine on northerly aspects.
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.