The fastest wind speed ever recorded, 318 miles an hour (511 kilometres an hour),      occurred during a tornado near Oklahoma City in 1999. A tornado with wind speeds of 70 miles an hour can sweep away houses and hurl cars through the air like missiles. And a tornado with wind speeds of more than 300 miles an hour has the power to derail train cars, tear grass from the ground, and even rip pavement from the street.