The ten day spell of icy weather that has swept across most of Switzerland is running out of steam as the warm Foehn wind starts to blow northward over the Alps. According to MeteoNews between now and Sunday, temperatures should turn positive across the plateau.
Today saw large temperature differences across Switzerland. Valais got a taste of spring with temperatures as high as 12 degrees, while Vevey, Lausanne and Geneva froze.
The Foehn can quickly bring sharp increases in temperature. In Bad Ragaz in the canton of Saint Gallen, the temperature jumped from – 10.1 degrees to +12 degrees in 30 minutes on Thursday evening, a jump of 22 degrees.
The warm dry Foehn is produced when winds from the Mediterranean, forced up by the Alps, drop their moisture on the southern slopes, leaving warm dry air to pass over the remaining Alpine region and beyond. The phenomenon can quickly drive temperatures up substantially.
The recent cold snap is the longest measured since February 2011, when freezing temperatures lasted 15 days.