Williwaw

In meteorology, a williwaw is a sudden blast of wind descending from a mountainous coast to the sea. The word is of unknown origin, but was earliest used by British seamen in the 19th century. The usage appears for winds found in the Strait of Magellan, the Aleutian Islands, and the coastal fjords of the Alaskan Panhandle, where the terms outflow wind and squamish wind are also used for the same p... (Wikipedia)