Tornado Alley
It has also been asserted that there are numerous Tornado Alleys. In addition to the Texas/Oklahoma/Kansas core, such areas include the Upper Midwest, the lower Ohio Valley, the Tennessee Valley and the lower Mississippi valley. Some studies suggest that there are also smaller tornado alleys located across the United States.
Tornado outbreak sequence of April 19–24, 2011
The tornado outbreak sequence of April 19–24, 2011 was an extended period of significant tornado activity that began on April 19th, 2011 and ended on April 24, 2011. It affected the Midwest and Southern United States. The outbreak produced an EF4 tornado that tore through the St. Louis metropolitan area. Other tornadoes caused damage in Illinois, Indiana, and Ohio. Amazingly, no fatalities were reported in this outbreak. However, it was later followed less than 48 hours later by the largest tornado outbreak in the history of the United States.