The first anniversary of the deadly Joplin, Mo., tornado is May 22, 2012. Here's a look at the 10 deadliest tornadoes in U.S. history, according to the NOAA.
8. Purvis, Miss. (1908) -- This EF4 tornado was reported to be two miles wide and hit parts of Louisiana and Mississippi. More than 700 were injured and 143 killed.