The wreckage of this home, in the aftermath of a tornado that struck Tuscaloosa, Ala., on April 27, demonstrates the tendency of some interior rooms to remain largely intact even when the rest of a structure has been demolished.
The wreckage of this home, in the aftermath of a tornado that struck Tuscaloosa, Ala., on April 27, demonstrates the tendency of some interior rooms to remain largely intact even when the rest of a structure has been demolished.

The 2011 tornado season has been one for the record books. A multi-state outbreak in late April killed at least 322 people in several southeastern states, with 238 of the deaths taking place in Alabama alone. A month later, a massive storm swept through Joplin, Mo., claiming an additional 151 lives. Even Massachusetts - a state not ordinarily viewed as particularly tornado-prone - was struck by an early-June twister that killed three. As of midsummer - with the storm season past its peak but by no means over - the nationwide death toll for 2011 stood at 537, making it the deadliest year since 1936.

The severity of a given tornado is often described in terms of the Fujita scale, or F-Scale, which ranges from F0 (characterized by wind speeds from 40 to 72 mph, capable of damaging chimneys and pushing over shallow-rooted trees) to F5 (wind speeds from 261 to 318 mph, causing near-total destruction of most buildings). Safe rooms - also known...

or Register to read the full article.