Storm slabs will likely build throughout the day. A MODERATE hazard may be the story in the am, but strong easterly winds and new snow is driving the danger to CONSIDERABLE in the alpine for the afternoon.
Confidence
Moderate - Intensity of incoming weather systems is uncertain on Thursday
Weather Forecast
Thursday: 10-20 mm expected and accompanied by strong easterly winds. Alpine temperatures near plus 1 with freezing levels 1800 m. Friday: Mainly cloudy with up to 10 cm of new snow. Alpine temperatures near -2 and freezing levels dropping to 1300 m. Ridgetop winds light with strong gusts from the southwest.Saturday: Mainly cloudy with 5 cm of new snow. Alpine temperatures near -3 and freezing levels 1300 m. Ridgetop winds light from the southwest.
Avalanche Summary
On Wednesday, several natural loose wet releases from sunny aspects and loose dry from northerly aspects were reported up to size 1. The avalanche hazard will rise with forecast wind and precipitation.
Snowpack Summary
Forecast new snow will likely have a poor bond to the plethora of old snow surfaces including a melt-freeze crust on sunny aspects, or surface hoar on north aspects above 1500 m. Isolated wind slabs just below ridgetop exist on northeasterly aspects and moist snow surfaces are found below 1500 m. Deeper in the snowpack, the mid-December and late-November weak layers are composed of crusts and sugary facets, which are down 150-300 cm. These layers are currently dormant.
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.