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.
1. Tri-State tornado (1925) -- This EF5 tornado killed 695 and injured more than 2,000 across Illinois, Indiana and Missouri. Records were set for both speed and path length.