Tornadoes are destructive forces of nature that can form quickly and devastate cities and communities, but with proper education and preparation, damage can be minimal. Tornadoes are defined as "a tall, narrow, violently rotating column of air (i.e., vortex), usually about 300 feet (100 m) in diameter, that extends to the ground from a cumulonimbus” (Davies-Jones 1). Tornadoes are known to form in the central part of the United States, and most of them form, but they can also form in many other parts of the world, including Russia, China, South Africa South and Australia. Tornadoes form from systems that have large-scale circulation patterns and are associated with severe cumulonimbus-filled thunderstorms. They were once thought to form when warm, moist air collided with cold, dry air, which was accepted because many form in spring, but this is actually not accurate. “The most destructive and deadly tornadoes originate from supercells, which are rotating thunderstorms with a well-defined radar circulation called a mesocyclone” (Edwards 1). In reality, temperature has little to do with the formation of tornadoes. The formation of tornadoes mainly depends on instability, wind updraft and air humidity. Severe thunderstorms accompanied by green skies, strong winds and large hail can form tornadoes, but this is not always the case. Some may form above water, but they are called waterspouts. There have been numerous tropical storms and hurricanes that formed tornadoes in the recent past that caused hundreds of millions of dollars in damage, in conjunction with the flooding and high winds that hurricanes already produce. Hurricane Danny in 1985 and Hurricane Ivan in 2004 produced numerous tornadoes...... middle of paper ......a list of items that could pose a problem if a tornado damaged the building. Families should also have a plan to keep themselves safe. After a tornado hits an area, there are dangers people should be aware of, including downed power lines, debris from buildings and other structures, and the possibility of new storms. The desire of large numbers of people to return home is expected but discouraged because it may interfere with rescue and damage control operations, including restoration of utility services and cleanup of possible hazardous spills. It is important that people listen to emergency information broadcast by radio and television channels to be aware of these dangers. The aftermath of tornadoes also creates risks of dehydration and heat injuries due to lack of fresh water supplies and electricity to keep areas cool..