Regions
Northwest Coastal.
Confidence
Fair - Due to limited field observations
Weather Forecast
Synopsis: A ridge of high pressure should maintain mainly sunny skies on Saturday and Sunday. Freezing levels should climb to 1400m on Saturday and 1600m on Sunday, and drop to valley bottom overnight. Upper level winds are light and variable. A weak system could spread more cloud and light precipitation on by Monday afternoon into Tuesday. The freezing level should hover around 1500m.
Avalanche Summary
Recent reports include wet loose avalanche activity up to Size 2.0 in response to direct sun exposure. Cornices have also been failing over the past couple of days, some of which triggered wind slab avalanches up to Size 2 on the slope below. Large glide avalanche activity also continued on solar aspects.
Snowpack Summary
The snow surface consists of a sun crust on solar aspects and lower elevations (becoming moist during the day), surface hoar on shady slopes up into the alpine, and dry settling or faceting snow on higher north aspects. Pockets of wind slab are likely in exposed leeward alpine terrain. Sheltered shady slopes may be harboring buried surface hoar and/or preserved old storm snow from last week, which isn't as stable. Not only will daytime warming and sun-exposure cause surface snow to lose cohesion and cornices to weaken, they will also increase settlement rates and decrease slab stability.
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.
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.