The sun will be out in force on Tuesday. As it rapidly warms the snowpack, there will be an increasing likelihood of avalanches.
Confidence
Moderate - Freezing levels are uncertain
Weather Forecast
TUESDAY: Sunny, moderate southwest wind, freezing level up to 2000 m after an overnight freeze.WEDNESDAY: Mix of sun and cloud, strong west wind, freezing level climbing to 2200 m with little overnight freeze.THURSDAY: Mostly cloudy with snow/rain starting later in the day, moderate southwest wind, freezing level holding at 2200 m.
Avalanche Summary
Several natural and skier triggered size 1-1.5 loose wet avalanches were reported on Monday. On Sunday, a few small storm slabs were triggered by explosive avalanche control and ski cutting and a size 2 slab was triggered by a natural cornice fall.On Tuesday, storm slabs may still be reactive at higher elevations. Warm sunny weather will also increase the possibility of loose wet avalanches and cornice falls.
Snowpack Summary
Daytime warming will create moist surfaces, especially on southerly aspects. 10-20 cm of recent dry snow can be found on northerly aspects above 1700 m. Elsewhere the surface snow is experiencing a daily melt-freeze cycle, forming thick supportive crusts overnight and moist snow during the day. The December facets and November rain crust are buried deep, and did not become reactive during the latest period of warm weather, rain, and strong solar radiation.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.