They are more frequent in winter than in the summer months, particularly in the eastern U.S. Summer windstorms are most often associated with thunderstorms, and bands of thunderstorms moving together can create widespread windstorms called derechos that are most common in the Midwest.

Why do windstorms occur?

Longer-period windstorms have two main causes: (1) large differences in atmospheric pressure across a region and (2) strong jet-stream winds overhead. Horizontal pressure differences may accelerate the surface winds substantially as air travels from a region of higher atmospheric pressure to one of lower.

Where do windstorms mostly occur?

Catastrophic windstorms were most frequent in the Central, Northeast, West, and Northwest climate regions, and least often in the High Plains. More than half of the catastrophes (56 percent) occurred in only one state.