Regions
Northwest Coastal.
Temperatures are forecast to rise through the day on Friday, peaking on Friday night and Saturday. If it warms up earlier and snow turns to rain expect higher avalanche hazard than posted for Friday.
Weather Forecast
Friday: Moderate to heavy snowfall – 20-40 cm (heaviest along the coast). The freezing level climbs to 1400 m in the south and 500 m in the north. Winds are crankin’ from the S-SW. Saturday: Moderate snowfall – 10-20 cm. The freezing level is between 1000 in the north and 1300 m in the south. Winds are moderate to strong from the S-SW. Sunday: Periods of snow. The freezing level is around 1400 m lowering throughout the day. Winds are moderate to strong from the S-SW.
Avalanche Summary
There are no new reports of avalanches from Wednesday. There's finally a weather change on the horizon! Expect conditions to start changing quickly on Friday and through the weekend.
Snowpack Summary
Persistent strong outflow winds (from the northeast-southeast) have scoured windward slopes and created hard or dense wind slabs in exposed lee and cross-loaded terrain. Cold clear weather has also promoted surface hoar growth and surface faceting on shady slopes and a sun crust on steep solar aspects. The mid February weak layer of surface hoar or a crust/facet combo is buried 30-90 cm deep. There has been no reported activity on this layer recently, but watch for it to wake up when the weather pattern shifts to moist and mild heading into the weekend. Basal facets and/or depth hoar remain a concern in shallow snowpack areas in the northern part of the region.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.