Extreme warming and solar radiation will drive the Avalanche Danger. Be alert to conditions that change throughout the day, and watch your overhead hazard. Large avalanches may run farther than expected.
Confidence
High - The weather pattern is stable
Weather Forecast
A dry ridge of high pressure will bring mainly clear skies for Thursday and Friday. Increased cloud and isolated flurries are forecast for Friday evening and Saturday. The freezing level will sit at about 3800m on Thursday, 3300m on Friday, and 2300m on Saturday. Ridgetop winds will remain mainly light and variable.
Avalanche Summary
In recent days, fresh wind slabs to size 1.5 were triggered under light loads in mostly north facing alpine terrain. With forecast warming and solar radiation, we'll see a transition to more spring-like avalanche problems. Loose wet avalanches, and large cornice falls are expected throughout the forecast period
Snowpack Summary
20-40cm of recent snowfall overlies a mix of old surfaces that formed as a result of last week's big warm-up. These include hard crusts on high elevation solar aspects, settled dry snow in north-facing alpine terrain, and moist snow everywhere else. The recent snow has been shifted by strong southerly winds into fresh wind slabs in wind-exposed terrain. With forecast solar radiation and warm temperatures, most surfaces will transition to a daily melt-freeze cycle, while recently formed wind slabs will linger on high north-facing slopes. Below the new snow, the snowpack is generally strong and well-settled. Cornices are huge and will become weak with future warming and solar radiation.
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.
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.