"sudden, violent gust of wind," 1719, originally nautical, probably from a Scandinavian source (compare Norwegian skval "sudden rush of water," Swedish skvala "to gush, pour down"), probably ultimately a derivative of squall (v.).
"cry out loudly," 1630s, probably from a Scandinavian source, such as Old Norse skvala "to cry out," and of imitative origin (compare squeal (v.)). Related: Squalled; squalling. As a noun from 1709.
When it squalls, a prudent sailor reefs his sails