Northwest Coastal

Avoid avalanche terrain during periods of heavy loading from snow and wind.

Moderate - Forecast snowfall amounts are uncertain

TUESDAY: Stormy with accumulations of 15-30 cm, strong west winds, temperatures around -4C.WEDNESDAY: Flurries with accumulations up to 10-20 cm, strong southwest winds, temperatures around -4C.THURSDAY: Cloudy with isolated flurries, moderate northwest winds, temperatures around -6C.

On Sunday, skiers in the northern parts of the region remotely triggered several size 2 avalanches that failed on weak facets at the base of the snowpack. This has been a regular occurrence in areas with thinner snowpacks. In the south where the snowpack is thicker, there have been no recent avalanche reports. However, observations were very limited over the holiday weekend and visibility was poor on Monday.On Tuesday, expect the new snow to form touchy storm slabs, particularly on wind-loaded terrain features. Storm slabs may 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 large and destructive.

The current storm is building touchy storm slabs throughout the region that may be up to 50 cm thick by Tuesday afternoon. Expect extra thick storm slabs in the lee of exposed ridges. The storm snow has buried 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.