Deadly Derecho Darkens D.C.


This June 28, 2012, image was taken acquired before the storm with the day/night band of S-NPP’s visible infrared imaging radiometer suite. Click on image to enlarge.

These before-and-after images from NASA’s Suomi National Polar-orbiting Partnership (S-NPP) satellite show the power outages in the clear skies over Washington, D.C., and Baltimore that occurred on June 29, 2012. The outages were the result of a derecho, a rare, fast-moving thunderstorm system that packs the power of a tornado.

The derecho combined intense lightning and rain with hurricane-force winds that were upward of 60 miles per hour. It killed 22 people and caused about 4.3 million households to lose power for days.

Of particular interest in this June 30, 2012, post-storm image is the loss of light to the north and west of Washington, D.C., along the Interstate 270 and 66 highways and Maryland route 267. Click on image to enlarge.

Derecho is the Spanish word for “straight.” True to form, the storm raced from west of Chicago straight across Illinois, Indiana, Ohio, West Virginia, Virginia, Maryland and into Washington, D.C. According to the National Weather Service, the gigantic windstorms of a derecho are as powerful as tornados, but the winds don’t twist, instead driving in a straight line. To be classified as a derecho, the swath of wind damage must extend more than 240 miles and the storms are powered by hot, humid weather.

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