Wind slab
- Above 1,800 m
Main danger: weak old snowpack layers. Fresh snowdrifts require caution.
Main danger: weak old snowpack layers. Fresh snowdrifts require caution.
Particularly in high-altitude ridgeline and pass areas, as well as behind drops in the terrain, fresh snowdrift accumulations are easy to trigger. It is possible to trigger slab avalanches in the old snow particularly by large additional loading. If a release sweeps away the entire snowpack the avalanche can grow to medium size. Danger zones are located especially on steep shady slopes, but also in wind-loaded gullies and bowls in all aspects. Whumpf noises and fractures on the surface are alarm signals. Activities in outlying terrain away from secured ski runs require experience in evaluating the terrain and assessment of avalanche dangers.
The most recent fresh snow was intermittently transported by strong-velocity winds. Particularly in ridgeline and pass areas, fresh, usually small drifted masses occur. Especially where fresh snow and drifts are deposited on top of surface hoar or on loosely-packed old snowpack layers, the bonding is moderate-to-poor. Small releases and fractures on the surface confirm the proneness to triggering of the snowpack. The old snowpack is overall unfavorably structured. Particularly on steep, shady slopes, weak intermediate layers persist inside the snow cover.
On Wednesday, southerly foehn winds will generate dispersed clouds and some sunshine. During the course of the day, air masses will become moist, clouds dense. In late afternoon, light snowfall is expected in many places. At 2000m: dropping from +1 to -4 degrees; at 3000m: from -5 to -8 degrees. Initially brisk southerly winds at high altitudes, later slackening off to moderate velocity.
At high altitudes, the unfavorably structured snowpack is the main danger. Avalanche danger will increase on Thursday due to fresh snow and winds.
Bulletin data: Avalanche Warning Service Vorarlberg (CC BY 4.0)