Continued stormy weather will trend the avalanche danger up over the weekend. If your area gets more snow than forecast, then these danger ratings may be a bit low.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Sunday
Weather Forecast
5-10 cm overnight with very strong southwest winds and freezing levels around 500 metres. Another 5-15 cm during the day Sunday with slightly lower wind values expected. Snowfall amounts may be locally higher in the south of the region around Manning Park and the Coquihalla. Continued light snow on Monday with moderate southwest winds and a chance of the freezing level rising up to about 800 metres. More light snow, cool temperatures, and increasing winds on Tuesday.
Avalanche Summary
Soft windslabs released naturally or were triggered by fresh cornice falls in the Duffy Lake area on Friday up to size 2.0
Snowpack Summary
Less new snow in the Duffy Lake area; 10 cm new on Friday with strong alpine winds building windslabs and cornices. There was 15-20 cm of new snow on Friday morning available to be transported into windslabs by moderate southerly winds. These new storm and wind slabs may be sitting on a new layer of surface hoar that was buried on Thursday. The new storm snow is above 40-50 cm of snow from last week, that may also be sitting on a buried surface hoar layer. There is about 100 cm of settled snow above the December 8th melt-freeze crust. There is about 200 cm at 1800 metres in the Coquihalla.
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.