May 24 2011 

Violent storms killed at least 13 people in the U.S. states of Oklahoma, Kansas and Arkansas on May 24. The storms, which came closely behind the deadly twister that struck Joplin, Missouri, moved into the Oklahoma City area Tuesday evening. 

• At least 13 people killed by violent storms in U.S.

May 22 2011 

A massive storm system dropped a devastating tornado into Joplin on May 22 evening, a city of 50,000 people in the southwest corner of Missouri, killing at least 116 people and leaving churches, schools, and homes reduced to ruins. 

• Deadly tornado leaves Missouri city in ruins

April 27-28 2011 tornado outbreak 

Massive tornadoes hit Southern, Midwestern, and Northeastern United States on April 27 and 28 2011, leaving catastrophic destruction in its wake, especially across the state of Alabama. The death toll from the storms reached 329 in seven states, including 238 in Alabama, making it the second-deadliest tornado outbreak in American history. 

• Combination of factors contribute to US deadliest tornado

April 14 -16 2011 tornado

This was one of the largest tornado outbreaks in United States history occurred in the communities of the southern United States, resulting in at least 200 confirmed tornadoes and 43 people's death. The tornados mainly passed through Alabama, Mississippi, Carolinas and southern Virginia.

• Storms across US East Coast [photos]

In history

2008 Super Tuesday tornado outbreak 

This was a deadly winter tornado outbreak which affected the Southern United States and the lower Ohio Valley on February 5 and 6, 2008. 87 tornadoes occurred over the course of the outbreak. At least 57 people were killed across four states and 18 counties, with hundreds of others injured.

• Dozens killed as tornados slam into southern US states