Tornado Alley
The term was first used in 1952 as the title of a research project to study severe weather in areas of Texas, Oklahoma, Kansas, South Dakota, Iowa, Missouri, Nebraska, Colorado, North Dakota, and Minnesota. It is largely a media-driven term although tornado climatologists distinguish peaks in activity in certain areas and storm chasers have long recognized the Great Plains tornado belt.
Tri-State Tornado
It was a widespread outbreak with severe thunderstorms occurring as far east as Ohio, as far southwest as Louisiana, and as far southeast as Georgia. Strong thunderstorms were reported in a broad area that also included parts of Oklahoma, Michigan, Ontario, Pennsylvania, and West Virginia. Numerous reports of hail and straight-line winds were reported with up to diameter hail recorded (for reference, a softball is in diameter). What began in the early-mid afternoon as discrete supercell thunderstorms eventually consolidated into a potent squall line.