How tornados are formed?

 They usually form in a giant rotating thunderstorm called a supercell. Supercells develop in warm, moist air in advance of eastward-moving cold fronts.The result is great instability caused by the rising warm air. After that, clouds form together to give life to a tornado.  These thunderstorms often produce large hail, strong winds, and heavy rain.
   Tornadoes come in many shapes and sizes, but when they touch the ground they do lots of damage. When tornadoes hit the ground they rip thru buildings and throw debris and dust into the air.