What’s a Derecho? Powerful Storm That Began in South Dakota.
Strong thunderstorms and winds whipped through eastern and southeastern South Dakota early today and continued a path through Iowa while having winds clocked at over 100 MPH in some areas. The town of Midway, Iowa recorded winds gusting at 112 MPH.
According to the National Weather Service, a Derecho is a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms. Although a derecho can produce destruction similar to the strength of tornadoes, the damage typically is directed in one direction along a relatively straight swath. As a result, the term "straight-line wind damage" sometimes is used to describe derecho damage. By definition, if the wind damage swath extends more than 240 miles and includes wind gusts of at least 58 mph or greater along most of its length, then the event may be classified as a derecho.
The system that continues to move in a southeasterly direction began building before sunrise Monday. Gregory, South Dakota had reports of 2-inch size hail. Burke, Tyndall, and Scotland and Rock Rapids, Iowa reporting 1-inch hail.