What Causes Windstorms?

According to Encyclopedia Britannica, windstorms result from large-scale weather systems such as thunderstorms, and the interaction of cold air and warm air on the earth's surface. The two main types of windstorms are cyclones and derechos.

Cyclones are giant, spinning, whirlwind storms that form when warm ocean water evaporates and forms clouds. According to The Australian Emergency Management Institute, the clouds begin to rotate if there is low air pressure where the clouds form. When the earth rotates and spins on its axis, the cyclone clouds continue to form and spin at a higher rate, eventually increasing the wind speed until there is a windstorm.

In order to be categorized as cyclone, a storm system needs to maintain wind speeds of 40 mph or more. A severe storm is one that manages to achieve wind speeds of 70 mph or more. Derechos are similar to cyclones because they also display sustained wind speeds; unlike a cyclone, which can move in multiple directions, derechos typically occur in one direction along a relatively straight path. According to the National Weather Service, the term "straight-line wind damage" sometimes is used to describe derecho damage. Derechos can extend for more than 250 miles and reach speeds of up to 75 mph, which makes them particularly destructive when they occur over land.