A derecho (pronounced similar to “deh-REY-cho” in English is a widespread, long-lived windstorm that is associated with a band of rapidly moving showers or thunderstorms. Although a derecho can produce destruction similar to that of a tornado, the damage typically occurs in one direction along a relatively straight path. As a result, the term “straight-line wind damage” sometimes is used to describe derecho damage. By definition, if the swath of wind damage extends for more than 240 miles (about 400 kilometers), includes wind gusts of at least 58 mph (93 km/h) along most of its length, and several, well-separated 75 mph (121 km/h) or greater gusts, then the event may be classified as a derecho. Many significant derechos (i.e., those that have caused severe damage and/or casualties), have occurred over North America during the last few decades. Most of these affected the United States and Canada.
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