Middle Lys Valley

The weather will be warm. Moist and wet avalanches as the day progresses.

The weather will be warm. Moist and wet avalanches as the day progresses.

At night, air temperatures will still be positive above 2900 m. In particular above approximately 2500 m and shady slopes: The early morning will see favourable conditions for a short time, but the danger of wet and gliding avalanches will increase later. As a consequence of warming and solar radiation, the natural activity of medium moist and wet avalanches will rapidly increase, in particular on very steep sunny slopes. This also applies at the base of rock walls, including on very steep shady slopes at intermediate altitudes. Additionally moist and wet avalanches can be released in deep layers reach large size in isolated cases in particular on very steep northeast, east and west facing slopes. Backcountry tours and off-piste skiing should be started and concluded very early.

Outgoing longwave radiation during the night will be quite good. The surface of the snowpack will soften quickly. The snowpack will be wet all the way through at low and intermediate altitudes. In the last few days the natural activity of medium wet and gliding avalanches has gradually increased. Several medium-sized to large ground avalanches have been released since Tuesday. This applies in particular on very steep northeast, east facing slopes. 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. Weak layers exist in the snowpack in particular on steep shady slopes. Below approximately 1800 m hardly any snow is lying.

The danger of moist and wet avalanches will persist. As a consequence of rain up to approximately 2500 m the snowpack can not consolidate.