One particularly long-tracked and devastating tornado hit the major cities of Tuscaloosa and Birmingham, Alabama, killing ...

On the Fujita scale, Enhanced Fujita scale, and International Fujita scale, F5, EF5 ... Australia, Canada, and Italy have each had one. Despite being rare, EF5 tornadoes are far more common ...

WOODWARD, Okla. — On April 9, 1947, one of Oklahoma's most devastating tornadoes hit Woodward. The powerful F5 tornado level 200 city blocks and killed more than 100 people in the city ...

which rated tornadoes from F0 to F5, based on estimated wind speeds and observed damage. Then, in 2007, the weather service adopted the Enhanced Fujita scale, which better reflected actual storm ...

As cool, dry air from Canada collides with warm ... Here are six of the costliest U.S. tornadoes. The F5 tornado that chewed through Joplin, Missouri, in 2011 remains the costliest twister in U.S.

It's one of the nation's most infamous tornado outbreaks, but it also spurred sorely needed improvements in both severe weather forecasting and safety.