Regions
Northwest Coastal.
Weather Forecast
Synopsis: A ridge of high pressure will maintain mostly sunny skies for the next few days. Wednesday and Thursday: The freezing level should rise to around 1000-1200 m during the day and drop back to valley bottom overnight. Outflow winds should ease off by Wednesday and we should generally see light winds from the north. Friday: Freezing levels could climb to 2000 m during the day on Friday.
Avalanche Summary
Recent reports include a few small natural wind slabs in steep lee terrain in response to northerly outflow winds. A few natural cornice failures, ice falls, and glide slab releases have also been reported. One cornice fall observed just north of Terrace triggered a size 3 slab avalanche that is suspected to have released on the late February weak layer. This event could have been a few days old.
Snowpack Summary
Outflow winds (from the north and east) have create new hard and soft wind slabs in exposed lee terrain. In sheltered areas the snow surface consists of facets, surface hoar, or a sun crust/ moist snow on south facing slopes. A layer of surface hoar, facets and/or a crust is buried down 50-90 cm, but most operators report a good bond at this interface. Watch out for cornices, as they are large and fragile. Several large cornice falls have been reported over the past few days. Most have not triggered slabs on the slopes below, however at least one triggered a very large avalanche. The mid snowpack layers are generally well settled and strong. Facets at the base of the snowpack have resurfaced as a concern now that spring is on the doorstep and full-depth releases are becoming more likely (primarily in the northern part of the region).
Problems
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.