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.
7. Joplin, Mo. (2011) -- The twister leveled homes and businesses and killed 161* people. *CNN and other news outlets have listed the death toll at 161; NOAA lists the toll at 158.