Northwest Coastal

Avoid all avalanche terrain. The incoming storm will produce large avalanches.

High -

SUNDAY NIGHT: Stormy with 10-20 cm accumulations and extreme southwest winds reaching 100 km/h at ridgetop.MONDAY: Stormy with accumulations of 20-30 cm, extreme 100 km/h southwest winds, temperatures around -10C.TUESDAY: Stormy with accumulations of 10-15 cm, 50 km/h west winds, temperatures around -10C.WEDNESDAY: Flurries with accumulations up to 10 cm, 50 km/h southwest winds, temperatures around -10C.

No new avalanches were reported in the southern part of the region on Saturday. In the northern part of the region, a size 3 avalanche was triggered with explosives. This avalanche failed on weak facets at the base of the snowpack, the same layer that skiers were remotely triggering avalanches on earlier in the week.On Monday, the new snow will form very touchy storm slabs. Storm slabs will be extra reactive in sheltered areas where they are burying a new surface hoar layer. The additional load of the new snow may also reawaken persistent weak layers buried about 1 metre deep. These layers produced large natural avalanches during last week's storm, and now there's some uncertainty as to how reactive they'll be during this storm. If they do release, the resulting avalanches will be very large and destructive.

Expect 20-50 cm of fresh storm snow by Monday afternoon, with extreme winds forming extra deep pockets. The storm snow will bury a layer of feathery surface hoar (up to 15 mm in sheltered areas), making wide propagations possible. A weak interface that formed during the early December cold snap can be found buried about 1 metre deep. The layer consists of weak faceted (sugary) snow, and preserved surface hoar in sheltered areas. The lower snowpack is well consolidated in deep snowpack areas. However, in areas with less snow, such as the northern parts of the region, there are also deeper layers of concern. These include a layer of surface hoar that was buried in mid-November and an old rain crust near the bottom of the snowpack that may have developed weak facets.