Northwest Coastal

The wet, warm, and windy storm will result in High avalanche danger.

Fair - Timing, track, or intensity of incoming weather system is uncertain

Heavy snow or rain below 1600 metres is expected to continue on Friday night. There may be a short break between storms Saturday morning, before the next 30-40 mm of precipitation combined with very strong Southwest winds and freezing levels up to about 2200 metres moves into the region. Expect another 10-15 mm of precipitation with moderate to strong Southwest winds on Sunday as freezing levels creep below 1500 metres. Monday should be drier with periods of flurries or showers, moderate winds, and freezing levels dropping below 1000 metres.

Very heavy loading from snow, wind, and rain has resulted in a widespread natural avalanche cycle up to size 4.0 on Thursday. Reports from Wednesday include numerous wind slab and some step-down persistent slab avalanches in the Size 2-3 range, with isolated deep persistent slab avalanches up to size 3.5 from large alpine features. Below approximately 1000m numerous wet loose snow avalanches up to Size 2.5 were observed running in steep terrain. This pattern should continue throughout the forecast period.

Heavy snowfall (with rain below approximately 1500-1000 m) and strong southwest winds have built fresh deep and dense storm and wind slabs. The slabs are likely 'upside down' with warm temperatures dropping moist dense snow on previous dry lower-density snow. A rain crust and/or surface hoar layer buried mid-December is down around a metre. Recent reports mention that this weakness has become 'electric' with recent heavy loading and has been responsible for much of the recent large avalanche activity. The November crust near the bottom of the snowpack is generally well bonded, but may 'wake up' with intense loading this week. There is potential for isolated very large and deep avalanches.