Regions
Northwest Coastal.
Strong solar radiation and mild temperatures this weekend could result in elevated avalanche danger during the day, particularly on sun-exposed slopes.
Weather Forecast
A ridge of high pressure should maintain mostly dry and sunny conditions throughout the forecast period. There is a chance of more cloud and light precipitation on Monday if a forecast frontal system pushes a little further north. The freezing level is around 900m on Saturday and 1200-1500m on Sunday and Monday. Winds are generally light from the south.
Avalanche Summary
On Thursday there were reports of a couple small (Size 1) accidentally triggered slab avalanches in steep, exposed, lee terrain features. There were also loose-wet avalanches up to Size 1.5 from steep solar aspects.
Snowpack Summary
Moderate SE winds have created thin wind slabs in lee and cross-loaded terrain. 20-40cm of new snow sits on the previous snow surface which included a sun crust on southerly aspects, surface facets or surface hoar in cool shady areas, and pockets of wind slab in exposed terrain. A variety of potential weak layers exist between 60 and 120cm deep. These include surface hoar or facets. There has been no recent activity on these layers but they could wake up with heavy triggers like a large cornice chunk or a snowmobile digging its track in. Cornices in the region are reported to be very large and potentially unstable.
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.
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.
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.