Wind slab
- Toutes altitudes
Main danger: fresh snowdrift accumulations and weak layers in the old snow
Main danger: fresh snowdrift accumulations and weak layers in the old snow
Fresh snow and snowdrifts are prone to triggering particularly in ridgeline zones, wind-loaded gullies and bowls and behind abrupt discontinuities in the terrain. They tend to increase with ascending altitude. Small to medium slab avalanches can be triggered by one sole winter sports enthusiast. If they fracture to deeper layers they can grow to large size. Also, above 2400 m on steep shady slopes there are unfavourable layers in the old snowpack. In very steep terrain and heavily wind-loaded zones, small slab avalanches and increasingly frequent slides can trigger naturally. As a consequence of rainfall at low altitudes, moist slides and small-glide snow avalanches on steep grassy slopes are possible.
The latest batch of fresh fallen snow (10 cm) was transported far-reachingly at high altitudes. The snowfall level will descend in the afternoon from 1400 to 1000 m. Fresh snow and drifts have settled and consolidated. They lie deposited atop loose and soft layers or melt-freeze encrusted old snowpack surfaces. Bonding deteriorates with ascending altitude. At high altitudes on shady slopes in particular, there are still weak layers evident deeply embedded inside the snowpack fundament. These danger zones are not visible to the naked eye.
On Thursday night: nighttime skies will remain dry, but with strong to stormy westerly winds. Friday: Strong to stormy westerly winds, visibility will swiftly alternate, rainfall and snowfall will focus on the northern massifs. In the afternoon, temperatures will drop, the snowfall level descend from 1400 to 1000 m. At 2000 m: -2 to -5 degrees. Strong to stormy westerly winds.
Saturday will be gloomy but dry, winds will be brisk, intensifying in the afternoon, from the west. Avalanche danger levels are not expected to change significantly.
Bulletin data: Avalanche Warning Service Vorarlberg (CC BY 4.0)