FOHN, a warm, relaxing wind experienced on the northern side of the Alpine range most frequently in winter and early spring. Similar local winds occur elsewhere, e.g., Norway, Green land and North America. In the last case it is known as the Chinook and descends the Rocky mountains to the western prairies, as a warm, dry wind which evaporates a great deal of the winter snow. The f ohn approaches the ridge from the south, is cooled during its ascent, and moisture may be condensed from it, giving rain or snow. It descends the northern slope by some process still obscure, during which it becomes warmed and dried, and has important local effects with reference to human activities. See Hann, Lehrbuch der Meteorologic, p. 594 ; and von Ficker, Innsbrucker Fohn-Studien (Wien, 1905) .