Northwest Coastal

Heavy snowfall, wind, and warming are a recipe for dangerous avalanche conditions! Rising temperatures throughout the day could increase the reactivity of storm slabs. 

Choose conservative terrain with no overhead hazard and continually assess changing conditions.

A juicy warm front is impacting the coast bring heavy snowfall overnight, strong southwest winds, and rising temperatures.

Saturday Overnight: Heavy snowfall, 20-30 cm accumulation. Strong to extreme southwest winds. Alpine temperatures rising to -5 C 

Sunday: Snowfall easing, 5-15 cm accumulation, heaviest in the afternoon. Strong to extreme southwest winds. Freezing levels rise to 500m with the potential for freezing rain or rime late in the day in the alpine and treeline.

Monday: Continued snowfall, 10-25 cm accumulation. Strong to extreme southerly winds. Freezing levels around 500m.

Tuesday: Snowing, 5-15 cm accumulation. Strong to extreme southwest winds. Freezing levels around 500m.

Natural and human-triggered avalanches are likely today. If you do see any avalanche activity, please let us know on the Mountain Information Network! 

On Thursday, operators north of Terrace reported a size 1 skier triggered persistent slab avalanche on an east aspect in an open area at treeline. This avalanche failed on a layer of surface hoar buried at the end of December. There have been no other reports of reactivity on this layer and it seems like a fairly isolated event. 

Overnight heavy snowfall, strong southwest winds and rising temperatures will have created a reactive storm slab problem on all aspects and elevations. Expect deeper, and more reactive slabs to be developing on north-east facing lees in wind-loaded areas. 

In open areas at all elevations, this storm's 20-60 cm of new snow overlies a stiff, previously wind-affected surface from last week's outflow winds. Near-surface faceting, and in isolated areas surface hoar growth, above the old surface may increase the reactivity of newly formed slabs.

The early December rain crust is up to 10 cm thick, down 80-150 cm in the snowpack, and exists to an average of 1400 m in elevation. Up to 2 mm facets have been reported above this crust, and it is producing hard but sudden planar results in snowpack tests in areas north of Terrace. While this layer has generally gone dormant in the region, it still has the possibility of waking up with new snow load or warming, and wind slab avalanches may still have the potential to step down to this deeper layer in isolated areas. 

• Watch for changing conditions today, storm slabs may become increasingly reactive.
• As the storm slab problem gets trickier, the easy solution is to choose more conservative terrain.
• Be careful to keep storm day fever from luring you out into bigger terrain features.