Regions
Northwest Coastal.
A series of strong frontal systems will affect the region resulting in HIGH avalanche danger throughout the forecast period. Travel in avalanche terrain is not recommended.
Confidence
Fair - Due to limited field observations
Weather Forecast
Snow should ease off on Sunday morning with a freezing level lowering to around 500-600m. Winds should be light to moderate from the W-SW. Another frontal system arrives on Monday bringing heavy snowfall and rising southwesterly winds to most areas through Tuesday morning. 40-70cm of snow is possible with a freezing level around 700m. Precipitation should ease off by Tuesday afternoon.
Avalanche Summary
Recent reports are limited to the highway corridors near Bear Pass and Terrace. Several natural avalanches up to Size 3 were observed, primarily in response to strong westerly winds. Explosive control produced a few Size 2-2.5 avalanches involving the recent storm snow. Both natural and human triggered avalanche activity should remain likely throughout the forecast period.
Snowpack Summary
Heavy snowfall continued on Saturday with some areas reporting more than 50cm of snow by mid-day. The snowpack depth near treeline is already around 300cm. Fluctuating freezing levels and varying precipitation intensity and wind throughout the recent storms has probably resulted in various weaknesses within upper snowpack. Widespread surface hoar was also observed on the previous snow surface at all elevations, but there is no recent information on this layer. The mid and lower snowpack is generally well settled and strong with an old rain crust near the ground.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.
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.