Border Pennine Alps

Wind slabs represent the main danger.

Wind slabs represent the main danger.

Since Monday the wind has been strong over a wide area. The clearly visible wind slabs of the last few days can be released, especially by large additional loads, in particular on west to north to east facing aspects at high altitudes and in high Alpine regions. On wind-loaded slopes the avalanches can be triggered in the various wind slab layers and reach medium size. In particular places where weaknesses exist in the old snowpack are unfavourable. Caution is to be exercised in particular in gullies and bowls, and behind abrupt changes in the terrain at intermediate and high altitudes. In particular very steep sunny slopes, intermediate and high altitudes: In steep terrain there is a danger of falling on the hard snow surface.

As a consequence of a strong northeasterly wind, clearly visible wind slabs formed since Monday in all aspects. In particular low and intermediate altitudes sunny slopes: The surface of the snowpack has frozen to form a strong crust. Adjacent to ridgelines in high Alpine regions snow depths vary greatly, depending on the infuence of the wind. At higher altitudes, snow cover becomes thinner and patchy; it is better at mid-altitudes, which are less exposed to the wind. The surface snowpack changes rapidly depending on the aspect and gradient: crusts of various types and thicknesses alternate. In steep terrain there is a danger of falling on the hard crust, especially adjacent to ridgelines and in pass areas. Sunshine and high temperatures will give rise to increasing consolidation of the snowpack.

As a consequence of warming during the day and the solar radiation, the likelihood of natural moist avalanches being released will increase a little on very steep sunny slopes.