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.
St. Louis tornado history
These tables describe the tornado history for Greater St. Louis. In Missouri, this includes the counties of St. Louis, St. Charles, Franklin, and Jefferson. In Illinois, this includes the counties of Madison, St. Clair, and Monroe. Data for the independent city of St. Louis is not part of these tables unless part of the path of the tornado striking these counties also struck the city.