Tornado Alley
Although the official boundaries of Tornado Alley are not clearly defined, its core extends from northern Texas, Oklahoma, Kansas, Nebraska, into South Dakota. States such as Missouri, Iowa, Minnesota, Wisconsin, Illinois, Indiana, and western Ohio are sometimes included in Tornado Alley. Some research suggests that tornadoes are becoming more frequent in the northern parts of Tornado Alley where it reaches the Canadian prairies.
Tornado outbreak of April 27–28, 2002
The Tornado outbreak of April 27–28, 2002 was a widespread outbreak that afectted areas of Iowa, Kansas, Missouri and Nebraska were affected on April 27. More tornadoes were reported in Illinois, Indiana, Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia on the following day, April 28.