Some parts of the region may see heavy precipitation on Monday, and the Avalanche Danger will rise throughout the day. Pay close attention to how much snow falls in your area, and be prepared to back off to simple terrain.
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Monday
Weather Forecast
10-15cm of new snow is forecast for Sunday night while similar amounts are expected on Monday. (Locally heavy accumulations are possible in areas east of the divide) On Tuesday and Wednesday the region will see a mix of sun and cloud as a ridge of high pressure develops over the province. Ridgetop winds should be moderate from the west on Sunday night, becoming strong and northeasterly by Monday afternoon. On Tuesday and Wednesday, winds will be light. Freezing levels will sit at about 1500m on Monday, and then rise to about 2000m on Tuesday and Wednesday.
Avalanche Summary
No new avalanches were reported on Saturday. I expect a new round of storm slab activity in response to new snow and wind on Sunday night and Monday.
Snowpack Summary
Large cornices loom above lee slopes at treeline and in the alpine. New snow and wind on Sunday night and Monday are expected to form potent new storm slabs. The new snow will overlie stubborn wind slabs in shaded high elevation terrain and a hard crust in most other places. Deeply buried weak layers near the ground are becoming hard to find, but may remain sensitive to triggering from significant warming or with large loads such as 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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.