Researchers are still exploring how a tornado develops from a thunderstorm, which is like a giant pump in which warm, moist air rises, cools, and condenses. When it has risen as high as possible, cloudy air spreads out into a characteristic anvil shape. As the air cools and condenses, rain forms and creates a downdraft. A difference in wind speed near the ground and higher up in the atmosphere can set the system rotating. But the transition of this rotation to the violent spinning of a tornado, and the fact that only a few rotating clouds produce them, remains a mystery.
Tornadoes are the shortest lived and most unpredictable of violent storms.
Tornadoes began in Indiana the morning of April 3, and ended early in the morning on April 4, in West Virginia and Virginia. A teacher and students rehearsing a play fled the auditorium seconds before the twister tossed two school buses through the wall and onto the stage. Hurricanes A hurricane is a heat engine that derives its energy from ocean water. When water evaporates, it absorbs energy. When water evaporates, it absorbs heat and as that water vapor rises and cools within the hurricane, it condenses, releasing heat that sustains the system.