From USA Today, comes an excellent description of the formation of tornadoes, by Josh Hatch, Bob Laird, Dave Merrill, Jerry Mosemak and Doyle Rice, USA TODAY.
“More than 1,000 tornadoes affect the USA each year, with many more going unreported. Find out how these monster winds form — many from supercell thunderstorms — as well as how to protect yourself from their fury.”
Go here for the graphics.