Confidence
Fair - Due to variable weather conditions
Weather Forecast
Moderate to heavy snowfall is forecast for Wednesday and possibly into Thursday with strong to extreme southwest winds. A mix of sun and cloud, reduced winds and intermittent flurries are forecast for Friday and Saturday. Daytime freezing levels area expected to remain at about 600m for the forecast period.
Avalanche Summary
Soft slab avalanches to size 1.5 were reported from the region on Tuesday. They formed in response to recent wind and snowfall. Expect ongoing storm slab avalanche activity with snow and wind forecast for Wednesday night.
Snowpack Summary
Expect widespread storm slab and wind slab formation in the wake of weather forecast for Wednesday. This will add to the 40-80 cm of recent storm snow that has been shifted into wind slabs on slopes lee to SE to SW winds. A couple of layers of surface hoar were buried last week in some areas. Snowpack test results on the surface hoar suggest an improving bond. The mid-pack is reported to be well settled and strong. A deeper layer of surface hoar from late November has been found intact or decomposing in some locations down a metre or more. The early November crust/facet combination near the base of the snowpack seems to be dormant. Triggering one of these persistent weak layers from a shallow snowpack area, or with a heavy trigger, remains possible.
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.