Wind slab
- All elevations
Avalanche danger increasing due to new snow and wind at high altitude
Avalanche danger increasing due to new snow and wind at high altitude
New snow and storm-strength NW winds are increasing avalanche danger to Danger Level 3 (considerable) above the treeline. Freshly-generated snowdrifts are prone to triggering, medium-to-large sized avalanches can be triggered even by minimum additional loading, i.e. by the weight of one sole skier. Avalanche prone locations will increase with ascending altitude and over the course of the day, especially in E/SW aspects, in gullies and bowls and behind protruberances, depending on wind impact also in forest clearances. Poor visibility makes it more difficult to assess the danger on-site.
At higher altitudes the new snow will often be deposited atop a smooth, melt-freeze encrusted old snowpack surface, initially amid little wind impact. The smooth surfaces are an unfavorable base for the bonded drifts, as the day unfolds the proneness to triggering is expected to increase. In places, facted weak layers beneath the melt-freeze crust can trigger the old snowpack. At lower altitudes, bonding of the moist old snow to the shallow snowpack is better, but trigger-sensitive drifts are being generated in forest clearances.
A powerful cold front and a low over Genoa will bring winter conditions back on Wednesday. Right from the start, most summits will be shrouded in fog, from the northwest snowfall will begin. By evening: 15-30 cm is expected, more from place to place. Snowfall level will descend by evening from 1200-1500 m down to valley floors in many areas. Winds will be strong to stormy, shifting gradually to northwesterly. Temperatures will continually drop: at 2000 m from -1 in the morning to -9 in the evening. At 1500 m: from slightly above zero to -6 degrees. On Thursday in the Northern Alps and northern Niedere Tauern, initially clouds and minor snowfall. As of midday, improving weather conditions, dispersed clouds. On the southern flank of the Alps, mostly pleasant conditions, but cold and windy.
Hardly any change in avalanche danger, trigger-sensitive snowdrifts remain the main problem.
Bulletin data: Avalanche Warning Service Styria (CC BY 4.0)