Lechquellen Mountains

Storm-strength foehn wind depositing new snowdrifts atop weak old snowpack

Storm-strength foehn wind depositing new snowdrifts atop weak old snowpack

Fresh, trigger-sensitive snowdrift accumulations blanket marked weak layers in the old snow: activities in backcountry demand cautious evaluation of the terrain and the dangers, as well as restraint. Caution is imperative in ridgeline zones, as well as in wind-loaded gullies and bowls. Avalanches which release can fracture to deeper layers in the old snowpack and grow to medium size. Such danger zones occur especially on steep shady slopes and are impossible to spot. Also remote triggerings are possible. Whumpf noises and fractures when treading on the surface are alarm signals. On sunny slopes, generally small loose-snow avalanches can trigger naturally during the course of the day. In addition, trigger-sensitive snowdrift accumulations will be generated during the day in foehn-exposed regions.

Fresh snowdrift accumulations lie deposited atop loosely packed snow or surface hoar in many places above the treeline, and also on top of a weak old snowpack surface, particularly on steep shady slopes. Avalanches triggered by winter sports enthusiasts and fractures on the surface confirm how prone to triggering the snowpack is.

Foehn wind impact: following a heavily clouded night of dry skies, the daytime hours will be quite sunny. Limited visibility on main ridge of Silvretta and Rätikon. Temperature at 2000m: +1 degree; at 3000m: -5 degrees. Strong to storm-strength southwesterly winds, with wind-chill, require caution.

Weak layers in the old snow can still be triggered by one single winter sports enthusiast. The likelihood of fresh drifts triggering will decrease during the course of the day only very little over the next period of time.