Weisseck, Muhr Valley

Daytime loss of firmness and high-alpine snowdrift accumulations

Daytime loss of firmness and high-alpine snowdrift accumulations

Avalanche danger above 2500m is MODERATE right from the start. Elsewhere danger is LOW in early morning, then rises to MODERATE by midday at latest.Danger zones for slab avalanches occur at high and high-alpine altitudes in NW/N/E aspects, in high alpine regions also in southern aspects in steep terrain. Particularly in connection with daytime warmth, even minimum additional loading can release a small-to-medium slab avalanche. Danger zones occur near ridges and in wind-loaded gullies, bowls.Naturally triggered wet loose-snow avalanches (also skier-triggered) and in some places even slab avalanches (up to 2600m) on sun-drenched steep slopes and isolated glide-snow avalanches in extremely steep grassy terrain are possible. They can grow to medium, in isolated cases also to large size.

The recent snowfall in high alpine regions has settled and has been moistened up to 2600 m at least superficially. The proneness to triggering in E/S aspects has receded. However, a foehn-induced southerly wind in exposed terrain has transported snow to north-facing slopes, generating mostly shallow snowdrift accumulations and depositing them atop a loose base: they are still prone to triggering. On steep sunny slopes the snowpack has a melt-freeze crust in early morning which is capable of bearing loads, then softens at varying quickness during the day depending on altitude and aspect. A potential weak layer: The smooth Sahara-brown snowpack layer, but isolated releases fractured deeper down.

On Wednesday, following a night of adequate outgoing longwave radiation, it will be sunny. Some diffuse light due to high-altitude clouds. In exposed terrain, moderate S/E winds. At 2000 m: very mild, 10 degrees. On Wednesday night, more clouds, but the outgoing radiation might still be able to regain firmness. On Thursday, favorable conditions to start with, with sunshine and some high-altitude clouds which can intermittently dampen the sunshine. In the afternoon a slight risk of showers. Winds will be brisk from the north. At 2000 m: 8 degree, at 3000 m: +2 degrees.

Due to noticeably higher temperatures, a pronounced daytime danger cycle for naturally triggered avalanche activity will continue. Good time management is crucial. In high alpine regions, give heed to potential wind-loaded zones.