Mon May 23, 2011

Twisters Untangled: Understanding Tornadoes

Tornadoes sometimes form in the midst of thunderstorms, when cold dry air meets warm, moist air. These conditions are most common in the region between the Rockies and the Appalachian Range known as "Tornado Alley". Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.