Regions
Kootenay Boundary.
Watch the temperature and solar warming! Heat and cornices are two great ways to shake-up the snowpack over the next couple of days.
Confidence
Fair - Timing or intensity of solar radiation is uncertain
Weather Forecast
Thursday: Snow should end overnight Wednesday with storm totals around 10 - 15 cm, having fallen with a moderate SW or W wind. Mixed sun and clouds, dry, temperatures below zero near treeline, except freezing level like to climb with solar radiation. Light to moderate NW wind.Friday: Very similar to Thursday except the wind should stay light from the NW.Saturday: A weak system expected to move in backing the wind to the S, increasing the clouds, light precipitation, and slightly warmer.
Avalanche Summary
From the reports we've received, avalanche activity has slowed right down with colder temperatures and the end of precipitation. Only reports from professionals were of snowballing and thin slabs on steep solar aspects.
Snowpack Summary
25 to 40 cm of snow from the previous storm was blown by strong winds into deeper deposits in lee terrain; the variable and shifting direction of those winds mean a complex pattern of lee and cross-loaded slopes. Rain at lower elevations saturated the snowpack. Colder, below freezing temperatures is turning the wet snow into a frozen crust; however, fresh snow above the rain-soaked layer is like a blanket of insulation and delays the freezing. These recent accumulations overlie crusts on sun-exposed slopes (SE - W aspects) and surface hoar in shaded terrain. Deeper in the snowpack is a facet/crust persistent weakness buried at the beginning of February, now down 70 to 160cm, has been highly variable in terms of reactivity but still shows 'sudden' results in snowpack tests. These layers are still difficult to trust and any avalanche at these deeper, persistent interfaces would be large and destructive.,Weak basal facets exist in some areas, but without a large load on the right piece of terrain, triggering is unlikely.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.