1. Any disturbed state of the atmosphere, especially as affecting the earth's surface, implying inclement and possibly destructive weather. There are at least three somewhat different viewpoints of storms. 1) In synoptic meteorology, a storm is a complete individual disturbance identified on synoptic charts as a complex of pressure, wind, clouds, precipitation, etc. , or identified by such mesometeorological means as radar or sferics. Thus, storms range in scale from tornadoes and thunderstorms, through tropical cyclones, to widespread extratropical cyclones. 2) From a local and special interest viewpoint, a storm is a transient occurrence identified by its most destructive or spectacular aspect(s). In this manner we speak of rainstorms, windstorms, hailstorms, snowstorms, etc. Notable special cases are blizzards, ice storms, sandstorms, and duststorms. 3) To a hydrologist, “storm” alludes primarily to the space- and time-distribution of rainfall over a given region. See local storm, severe storm. 2. See magnetic storm 3. (Also called storm wind, violent storm. ) In the Beaufort wind scale, a wind with a speed from 56 to 63 knots (64 to 72 mph) or Beaufort Number 11 (Force 11).