Cornices and daytime heating remain the primary concern today. Watch for changing snow conditions throughout the day, and with changes in aspect and elevation. Even small moist sluffs could bury a person.
Weather Forecast
Clear skies will be replaced by a small disturbance today, bringing partial cloudiness for part of the day. An upper ridge will re-build again tonight. The long weekend looks mostly sunny and clear, with warm temperatures and elevated freezing levels. Minimal or no precipitation, and light winds are expected.
Snowpack Summary
The generally well settled snowpack is being affected by strong solar radiation. North aspects are remaining cool, but sunny aspects and all lower elevations are warming up substantially during the day. Thin snowpack areas will be most susceptible, specifically on S and W aspects. Several PWLs (mostly buried sun crusts with SH) are still active.
Avalanche Summary
Numerous moist avalanches were reported yesterday from Asulkan and Connaught, and along the highway corridor. Most of these are scrubbing the surface snow, but a few are digging into deeper layers. Cornice triggered avalanches have increased throughout the area, with warm daytime temperatures, some of which broke down to deep PWL's.
Confidence
The weather pattern is stable
Problems
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.
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.
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.