When the cap gives way under the pressure of rising warm air, it releases a huge amount of energy in the form of an upward moving air mass. Air currents move in from all sides to replace the rising warm air and some times form a tornado. Usually, this does not happen. Wind at high altitudes plays an important role in determining whether a tornado develops. Depending on conditions, these winds can intensify the sudden upward air flow and create the vortex of wind that is a tornado.
Tornadoes can happen anywhere in the world.
However, due to certain conditions, the Midwestern United States is where they happen most frequently. An average tornado lasts only 10 minutes and travels up to 10 to 12 kilometers.