2011 marked a huge spike in tornado activity in the United States. 1,704 confirmed tornadoes killed 553 people. This includes 158 deaths from the category EF5 tornado that struck Joplin, Mo., on May 22. The Joplin tornado is the deadliest since modern record-keeping began in 1950.
(Image: © Karl Tate, Livescience.com Infographics Artist)