How do twisters form?
Most tornadoes come from thunderstorms, although some of the weaker ones form in cumulus clouds that are large and growing, but haven’t become thunderstorms. Any tornado is a swirl of air that’s rising into its parent cloud. Scientists are still trying to work out the details of what supplies the twisting motion. USATODAY.com has text explaining the basics of tornadoes that should help answer some of your questions. Then you could check our tornado index for links to more information, both at USATODAY.com and outside sources. You could also go to our graphic on supercell thunderstorms, which are the source of the strongest tornadoes.
