The Tri-State tornado of March 18, 1925 was very dangerous, as it was a very large, violent, and fast moving tornado that was difficult to recognize because of the low cloud base. Occurring in a time before there were tornado warnings, this tornado claimed 695 lives, making it the deadliest tornado in U.S. history.
Another one was the Waco, Texas tornado of May 11, 1953. It didn't move as fast as the Tri-State tornado, but it was of similar strength and was surrounded by rain, which made it impossible to see to the naked eye. With 114 deaths this tornado was tied as the deadliest in Texas history.
The Hackleburg, Alabama tornado of April 27, 2011 had some similarities to the Tri-State tornado. This fast moving tornado traveled at 60 mph and was, at times, over a mile wide. Despite warnings this tornado killed 72 people, making it the deadliest tornado in Alabama history.
The Joplin, Missouri tornado of May 22, 2011 moved at about average speed, but it developed and strengthened extremely quickly, reaching EF4 strength only 4 minutes after touching down and EF5 strength not long after. Despite warnings this tornado killed 158 people, making the deadliest U.S. tornado since 1947.
The worst tornado was the Daulatpur-Salturia tornado in Bangladesh, it killed more than 1300 people but its intensity is unknown.
In a violent tornado the worst features are flying debris and suction vortices, small whirlwinds that have stronger winds than the rest of the tornado.
The worst level of tornado that can strike is an EF5.
Probably the worst, or at least the deadliest tornado in the world was the Daulatpur-Salturia in Bangladesh on April 26, 1989.
The worst tornado to hit Cowley County Kansas was the Udall, Kansas F5 tornado of May 25, 1955. This tornado killed 80 people, making it the deadliest tornado in Kansas history.
The worst tornado was the Daulatpur-Salturia tornado in Bangladesh, it killed more than 1300 people but its intensity is unknown.
The worst tornado of 2012 would probably be the EF4 tornado that hit the towns of Henryville, New Pekin, and Marysville in Indiana on March 2, killing 11 people.
Spring is when the U.S. generally has the worst tornadoes.
The worst (or at least the deadliest) tornado to hit the U.S. was the Camilla, Georgia tornado of February 13, which killed 11 people.
the top
The worst tornado of 2005 was an F3 that killed 25 people in the town of Evansville, Indiana.
The worst level a tornado can attain is F5 on the old Fujita scale or EF5 on the newer Enhanced Fujita scale.