Northwest Coastal

Forecast moderate snowfall, and very strong winds will see the Avalanche Danger remain at High in the alpine and treeline elevations.

Poor - Freezing levels are uncertain

Tonight and Sunday: The upper low breaks down and begins to move east. However, moderate to heavy precipitation amounts (upwards of 20mm) continues this evening and tomorrow will see moderate amounts (15-20mm). A strong pressure gradient will maintain strong-extreme southwest winds at ridge top. Freezing level should lower to 700m by Sunday.Monday: Westerly onshore flow will see continuation of strong westerly winds and light precipitation. Freezing levels hovering around 600m.Tuesday: Another large storm hits the Northwest with heavy precipitation and strong southwest winds. Freezing levels may spike again during the brunt of the storm.

Numerous size 2-3 avalanches were observed in the bear pass area.  These mainly occurred on north through east slopes that are lee to strong southwest winds.The warm new snow is likely not bonding well to the weak layers formed in early december.  I suspect heightened avalanche activity and conditions will continue through Sunday.  Lower elevations have likely experienced a cycle of moist or wet natural avalanches releasing at or near the ground.  This should become less of a problem once the freezing levels start descending back down to valley bottoms.

A mixture of heavy rain/snow/wet snow has likely fallen to 1500m elevation. Strong Southwest winds are transporting snow and developing deep pockets that are sitting above recent weak surface layers. Rising temperatures during the storm have likely developed a relatively warm storm slab above a cold layer of wind crusts, surface hoar and surface facets, an upside down scenario. This layer was buried anywhere from 30-50cm prior to the major Dec 14 storm.Earlier in the week, reports from the Shames area at 950m elevation suggested the mid and lower snowpack was composed of various faceted layers and a stiff 4 cm crust. Another crust can be found closer to the base of the snowpack. The new storm is a great deal of change for this young and weak snowpack to handle.