The foehn effect and Mont Viso

In Italy, behind the crest that marks the border, the nebbia (fog) is often thick and only Mont Viso rises above the clouds. A damp wind comes up from the Italian side. The more it rises, the cooler and drier it becomes. This weather phenomenon can produce clouds and rain. Once past the mountain pass, the air descends, heats up and takes on more moisture. The sky on that side is clear and the temperature increases. This is called the foehn effect.