How tornadoes form How Tornadoes Form 1.
Air masses meet It takes special conditions for a tornado to occur.
Normally it takes two different types of fronts for a tornado to occur. A cold front is when the cold air is advancing and a warm front is when warm air is advancing. Difference in the winds caused by the pressure of the two different air masses starts a rolling motion moving upwards in the tornado. In the middle a sucking action and fierce winds cause the destruction. Links to more tornado information.