Avalanche forecast

Moderate-to-strong SW foehn wind generating fresh trigger-sensitive snowdrift accumulations

Moderate-to-strong SW foehn wind generating fresh trigger-sensitive snowdrift accumulations

The fresh snowdrift accumulations can be triggered by one single skier above 2000 m, especially in W/N/SE aspects. Avalanches can grow to medium-to-large size. Avalanche prone locations occur on steep slopes near to and distant from ridges, behind protruberances and in wind-loaded gullies and bowls. Weak layers in the old snow can be triggered by one sole skier/boarder, particularly in Rätikon, Silvretta and Verwall on NW/N/NE facing slopes, and then grow to large size. Activities in backcountry demand experience in assessing avalanche risks on-site. In addition, solar radiation and warmth can cause naturally triggered small-to-medium loose-snow avalanches on steep sunny slopes. At intermediate

Winds were only light-to-moderate yesterday, shifting in the afternboon over east to southwest. A strong easterly wind intensified briefly in east-west passes, then a moderate-to-strong SW foehn rose at high altitudes. Fresh, trigger-sensitive snowdrift accumulations were generated. The earlier drifts have settled somewhat on sunny slopes, their proneness to triggering receded. On shady slopes the drifts are not well consolidated, avalanches are still possible. The snowpack shows immense signs of wind impact: exposed zones are hard and windblown, leeward slopes, gullies and bowls are filled to the brim with drifts. In the Rätikon, Verwall and Silvretta the snowpack has weak layers. In those regions avalanches which are triggered can fracture down to these deeper layers and grow to large size. At intermediate altitudes the snowpack is moist, which reinforces gliding movement over smooth slopes.

Following a night of clear skies, Thursday will start with much sunshine, only a few cirrus clouds. Later in the morning more cloud cover will move in, impairing the sunshine in the afternoon, creating diffuse light conditions. No fog. Temperature at 2000 m: +1 degee. Moderate westerly winds at high altitude.

In the early part of the night on Thursday, gusty W/SW winds will bring some showers to the northern regions. In early morning, heavy rainfall and snowfall will start. Avalanche danger will increase somewhat.