Recent new snow is settled into a storm slab. This new snow combined with wind has promoted wind slab development as well as cornice growth. As the clouds part in the coming days remember that the sun packs a punch this time of year.
Confidence
Moderate - Timing or intensity of solar radiation is uncertain
Weather Forecast
MONDAY: Mix of sun, cloud and isolated flurries / Light to moderate west wind / Alpine temperature -5 / Freezing level 1200m TUESDAY: Mix of sun, cloud and isolated flurries / Light to moderate southwest wind / Alpine temperature -6 / Freezing level 1100m WEDNESDAY: Mix of sun, cloud and isolated flurries / Light to moderate southwest wind / Alpine temperature -5 / Freezing level 1200m
Avalanche Summary
Through the weekend avalanche activity included several natural and explosives controlled storm and wind slab avalanches size 1.5-2.5. These occurred on all aspects from tree line into the alpine. On Thursday and Friday, explosives control in the Fernie area produced loose dry and storm slab releases reaching from size 1.5 to 2.5 with some slabs reaching up to 80 cm in depth.
Snowpack Summary
50-60 cm of new low density snow accumulated in the region over Friday night. This brings snowfall totals from the past week to about 100 cm. This storm snow overlies various old surfaces including old hard wind slabs, crusts, facets and more isolated surface hoar. Also in the upper to mid snowpack, a surface hoar layer buried mid-February is now 80 to 100 cm below the surface on sheltered northerly aspects. Deeper in the snowpack, the widespread mid-December weak layer sits about 200 cm deep. This consists of a crust, facets or surface hoar. Near the base of the snowpack, a crust/facet layer could be awoken from a thin-spot trigger point, or with a very large load like a cornice fall.
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.