Avalanche danger will increase dramatically above the rain line, with human triggered avalanches likely on steep slopes.
Fluctuating freezing levels and heavy precipitation make it difficult to pinpoint what elevations will form storm slabs, but higher elevations could have up to 50 cm of fresh snow and very touchy slab conditions. Dial back your terrain choices if you observe more than 20 cm of new snow. Strong alpine wind could still produce natural avalanches on freshly loaded alpine features.
Cool dry weather after a cold front crosses Sunday night and delivers a final rain/snow mix to the South Coast mountains.
SUNDAY NIGHT: Another 20-30 mm of precipitation with snow levels somewhere around 1200 m, strong west wind, treeline temperatures near 0 C.
MONDAY: Clearing skies and dropping temperatures in the morning, gusty west winds, treeline temperatures around -2 C.
TUESDAY: Mix of sun and cloud, moderate northwest wind, treeline temperatures around -3 C.
WEDNESDAY: Mostly sunny, light wind, treeline temperatures around -3 C.
Periods of heavy snowfall and wind will likely drive a natural avalanche cycle on Sunday night, while lower elevations may experience wet loose avalanches triggered by the rain. Preliminary reports from Sunday show some small reactive storm slabs during the early stages of the storm (MIN report). Human triggered storm slabs will remain likely at treeline and alpine elevations on Monday.
Snowpack conditions will change dramatically with elevation. At lower elevations wet snow will be freezing into a hard surface crust throughout the day. Expect increasingly deeper deposits of new snow between 1000 and 1500 m, potentially up to 40 cm. The new snow should strengthen relatively quickly, but I'd carefully watch for signs on instability in areas with more than 20 cm of snow and avoid steep convex slopes. Alpine terrain could have upwards of 50 cm of new snow with heavily wind affected slabs in open terrain.
