|foehn also föhn |
A warm, dry, and often strong wind coming off the lee slopes of a mountain range, especially off the northern slopes of the Alps. A foehn is a katabatic wind that warms as it descends because it has dropped its moisture before crossing the mountain range and is put under greater atmospheric pressure as it moves downward. Various local names are also used for foehns (such as chinook in the Rocky Mountain regions). A foehn can cause sudden and dramatic increases in the temperature—from 10° to 20°C (50° to 68°F) in a few minutes—which can cause snow to melt rapidly and even trigger flooding. See also chinook.