These danger ratings are for the south of the region where forecast snow amounts are higher than Whistler, Pemberton, and further north.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain on Sunday
Weather Forecast
Snow starting Saturday afternoon is forecast to continue overnight combined with very strong southerly winds. Expect 15-25 cm by Sunday morning with a chance of enhanced snowfall in the southwest of the region. Continued snowfall should bring another 10-20 cm during the day on Sunday. Snow continuing Sunday night and Monday with moderate southwest winds. Another system is poised to move onto the coast on Tuesday. Freezing levels remaining around 500 metres during the forecast period.
Avalanche Summary
No new natural avalanches reported. Skiers have reported easy to trigger pockets of windslab up to 100 cm deep that have been confined to steep un-supported features and have not run far.
Snowpack Summary
Cold and dry new snow continues to fall in the region. Moderate to strong winds in the alpine have created pockets of windslab that may be up to a metre deep, but have not been propagating long fractures. There may be a slight change in the hardness of the snow down about 50 cm due to temperature changes of individual snowfalls. This may be the most likely depth for shears in snowpack tests. The December 8th crust is down about 100 cm and has been reported to be well bonded. The storm snow is the biggest problem at this time. It may be difficult to forecast when the incremental storm amounts combine to create enough loading over a weakness to result in large avalanches.
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.