Using a special simulator, he explains how tornados start with a thunderstorm which because of rapid uplift and wind shear, develop into a vortex of enormous power. Assistant Director Sally Duensing explains how the interaction of light with the eye often tricks our brains into seeing things that are not really there. This installment of technological failures features a variety of planes from the past that never quite got off the ground. A tornado is a narrow, short-lived, funnel shaped cloud usually not more than 100 meters across.
Tornadoes usually form as part of a line of particularly violent thunderstorms.
Strong updrafts caused by unequal heating of Earth's surface make cooler surrounding air rush in to fill the void. As these winds push in, the entire mass starts to rotate in a counterclockwise direction, forming the vortex and accelerating the force of the spin. Air pressure in the center of the vortex may be as much as one third lower than in the surrounding air, causing air in sealed buildings to rapidly expand and blow the windows out. Here, warm moist air from the Gulf of Mexico moving west runs into cool dry air coming eastward over the Rocky Mountains. The cool air first overrides the warm air, but being denser, it sinks forcing the warm air underneath to rapidly rise.