Regions
Kootenay Boundary.
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
A series of weak disturbances will result in light intermittent snowfall during forecast period. Freezing levels are expected to rise to as high as 2000m by Wednesday. Tuesday: Scattered flurries 3-5cm, freezing level rising to around 1500m, ridgetop winds 30-50 km/h SWWednesday: Snow or rain 6-10mm, freezing level around 2000m, ridgetop winds 40-60 km/h SW-WThursday: Snow or rain 8-12mm, freezing level around 1800m, ridgetop winds 30-50 km/h SW
Avalanche Summary
Explosive control on Monday produced numerous size 2 storm slab avalanches.
Snowpack Summary
The primary concern remains a persistent slab (typical thickness 50-90cm) from the last series of storms that is sitting on a stubborn persistent weak layer consisting of facets, surface hoar, melt-freeze crusts, or any combination of these. This weak layer is widespread at all elevations and aspects. Recent test results are suggesting that the layer is still easy to trigger in some areas but may becoming harder to trigger in other areas. We are still receiving isolated reports of large settlements or whumpfing which suggests the layer still has the potential for large propagations. In many areas the layer has the potential to produce large, destructive avalanches. The phase we are now entering is referred to a 'low probability/high consequence' problem. Continue to use conservative terrain choices until you are sure the layer is no longer unstable in your local area. Strong forecast winds from the SW are expected to create touchy new wind slabs on leeward slopes and cross-loaded features. As more snow accumulates we can expect a more widespread storm slab. This slab sits on top of surface hoar up to 10mm, near-surface facets, and/or a sun crust on south facing slopes.
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.