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, track, or intensity of incoming weather system is uncertain
Weather Forecast
Thursday night and Friday: Light flurries with a mix of sun and cloud / Light to moderate northwest winds / Freezing level at 800mSaturday: Flurries with a mix of sun and cloud / Light to moderate northwest winds / Freezing level at 800mSunday: Flurries with a mix of sun and cloud / Light to moderate northwest winds / Freezing level at 1200m
Avalanche Summary
Although observations were limited, I expect there would have been a round of storm slab activity in response to new snow and wind on Thursday. Looking forward, forecast sunshine may spark a loose wet avalanche cycle.
Snowpack Summary
In general about 35cm of new snow fell on Thursday adding to an existing storm slab which formed last weekend. Wind data was scarce on Thursday, although I suspect the new snow exists as a wind slab in exposed lee terrain. Below the recent storm snow you may find weak surface hoar in shaded terrain and a crust on previously sun-exposed slopes. About 60cm below the surface you'll find a strong rain crust which exists on all aspects below 2000m. This crust is widespread in the south of the region where heavy rain fell on March 10. As you head north in the region where the mountains are higher and colder temperatures persisted, this crust is less likely to exist.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 some snowpack tests. In areas where the strong and supportive near surface crust exists, triggering this layer has become unlikely. That said, this layer is still difficult to trust and any avalanche at these deeper, persistent interfaces would be large and destructive.,
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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.