The Power And Danger of Derecho

MessageToEagle.com – A derecho is a widespread, long-lived wind storm associated with rapidly moving showers or thunderstorms. It’s powerful and dangerous.

Its winds are at least 58 mph (50 knots or 93 km/h) or greater along most of its length. While derecho winds typically are less than 100 mph, gusts as high as 130 mph have been recorded.

Most derechos span at least 50 miles (80 km) in width.

The Line Storm by John Steuart Curry, 1897-1946. Source: The Smithsonian.

The word “derecho” was coined by Dr. Gustavus Hinrichs, a physics professor at the University of Iowa in 1888. “Derecho” is a Spanish word meaning “direct” or “straight ahead.”

Those outdoors are most at risk in a derecho. Campers or hikers in forested areas are vulnerable to being injured or killed by falling trees, and people at sea risk injury or drowning from storm winds and waves that can overturn boats. Occupants of cars and trucks also are vulnerable to falling trees and utility poles.

Gust front "shelf cloud" (or "arcus") on the leading edge of a derecho-producing convective system. The photo was taken on the evening of July 10, 2008 in Hampshire, Illinois as the storm neared the Chicago metropolitan area. The derecho had formed around noon in southern Minnesota. (Courtesy of Brittney Misialek) — Gust front “shelf cloud” (or “arcus”) on the leading edge of a derecho-producing convective system. The photo was taken on the evening of July 10, 2008 in Hampshire, Illinois as the storm neared the Chicago metropolitan area. The derecho had formed around noon in southern Minnesota. (Courtesy of Brittney Misialek)

High profile vehicles such as semi-trailer trucks, buses, and sport utility vehicles may be blown over. Even those indoors may be at risk for death or injury. Mobile homes, in particular, may be overturned or destroyed, while barns and similar buildings can collapse.

At outside events such as fairs and festivals, people may be killed or injured by collapsing temporary structures and flying debris.

However, a derecho rarely occurs without warning.

MessageToEagle.com

source: SPC NOAA