What is a derecho?

Published On: Jun 13 2013 10:27:06 AM CDT   Updated On: Jun 30 2013 07:14:45 PM CDT

Duh-what-choo? Find out more about the possible derecho threatening millions of Americans.

Storm clouds in NC
10 / 12
Alexandra Thickel/CNN

Another derecho is thought to have occurred in North Carolina on April 15, 1999, producing a killer tornado and a 165 mph wind gust, although this may have been associated with a tornado.

Upload Photos / Videos