Avalanche danger is increasing as the Pacific storm brings snow and wind to the Northern Interior.
Confidence
Poor - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Overnight and Friday: 10-15 cms is forecast overnight as Pacific moisture collides with cooler air over the Interior. Convective snowfalls at times heavy are expected in the North and West of the region. Moderate Southwest winds and freezing levels at valley bottoms.Saturday:Another 10-20 cms as the next strong pulse of Pacific moisture moves inland from the Northwest. Winds increasing to strong from the Southwest. Freezing levels rising quickly to about 1500 metres.Sunday:Snow tapering off to flurries. Winds remaining strong from the West. Freezing levels and temperatures dropping.
Avalanche Summary
No new avalanches reported. Expect avalanche activity to increase with forecast new snow and wind.
Snowpack Summary
Incremental new snowfalls of 10-15 cms continue to add a new storm load above the recently buried combination of wind slabs, crusts, surface hoar, and surface facets. Rising temperatures forecast over the next few days are expected to consolidate the storm slab above these buried weak layers. It may be difficult to determine when the slab will become more sensitive to light triggers like skiers and sledders. These weak layers are expected to be persistent, although in many areas the upper slab is not yet stiff enough for slab avalanches. When temperatures rise, and we get additional snow, expect this interface to become more reactive. The height of snow is below average for most of the region and below minimum recorded levels in many areas.
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.