today is the 50th anniversary of the 1974 super outbreak. 335 people died, with the strongest tornado having winds up to 305 mph, which almost got it rated an f-6, which doesn't exist. it had 148 tornadoes, making it the one of if not the most expansive tornado outbreak.
TeffyD
It helped Ted Fujita in his quest to optimize his scale. The almost F6 was the Xenia, OH one.