United State's Worst Tornadoes_The following is a representative list of the most important tornadoes in each state. The criteria for the "worst" in each state is different for each state. In some tornado-prone states, it is strictly based on deaths. In other states, it is based on deaths and injuries. In the states that have never had a tornado death, the selection is made on the basis of damage. Of course, the worst tornado in Nevada is less destructive that even the 500th worst tornado in Texas, Mississippi, or a dozen other states. To give at least some perspective on each state, rather minor events must be included for states where tornadoes are rare. We also change the criteria in 1953.

Since that year, forecasting and awareness efforts have drastically reduced the size of single-tornado death tolls in most states. If only the deadliest tornadoes were listed, then few recent events would be included.
The limitation of space does not allow a listing of every significant tornado. Each state has at least one listing. The listed death or injury total is only for that state, although some caused fatalities in neighboring states. Morning times are emphasized by printing AM in upper case letters. The list of killer and significant tornadoes was derived from the book "Significant Tornadoes" by Thomas P. Grazulis, director of The Tornado Project.

source: tornadoproject