A derecho is a widespread, long-lived line of thunderstorms that generates destructive straight-line winds, often causing damage comparable to that of a hurricane or tornado. These powerful storm systems can last for eight hours or more, traveling hundreds of miles with wind gusts typically exceeding 60 mph.
Though relatively uncommon, with some years passing without a single recorded event, derechos can occur almost anywhere in the United States. They are most prevalent in the central and eastern regions, especially during their peak season in July and early August when hot, humid, and unstable air provides the necessary fuel.
There are several types of derechos. Progressive derechos are common in the summer, forming on the northern edge of large heat domes where atmospheric instability is high, often intensified by humidity from crops. Serial derechos are associated with larger storm systems and typically occur in the spring and fall.
The damage from a derecho can be far more widespread than that of a tornado. While a violent tornado’s path is usually less than a mile wide, a derecho can carve a swath of destruction over 100 miles in width. These systems can also produce heavy rainfall, leading to dangerous flash floods, and may even spawn smaller, embedded tornadoes.
Historically, derechos have caused significant devastation. A 2009 “Super Derecho” traveled more than 1,000 miles from Kansas to Kentucky, causing several fatalities and over $500 million in damages. In 2020, a derecho with hurricane-force winds reaching 100 mph tore across the Midwest, leveling an estimated 100,000 trees in Cedar Rapids, Iowa, alone. Another event in December 2021 spawned at least 45 tornadoes across the Great Plains and Upper Midwest, resulting in five deaths.
Given their rapid development, experts advise monitoring weather forecasts and having access to a sturdy shelter. “It can go from nice, calm weather to 100 miles per hour winds blowing down trees in literally a matter of minutes,” said Gino Izzi, a meteorologist with the National Weather Service.
Source link
