A tornado is a violently rotating column of air that extends from a thunderstorm cloud to the earth's surface. The winds in the tornadoes are usually 100mph or less. They usually stay on a track of a few miles or less and are less than 100 yards wide.
For the development of tornadoes there are a few conditions required. An abundant low-level of moisture and unstable atmosphere is required not only for the tornado, but for a thunderstorm also. A "trigger", which is a cold front or low-level zone of converging winds, is needed to lift the moisture and the air. When the air rises, it becomes saturated and continues to rise higher and higher. They then form in areas where winds at all levels of the atmosphere are strong and turn clockwise with height. Some tornadoes appear as a funnel shape and some have a churning smoky look. .
Tornadoes can occur at any time of the year, and anywhere in the world. The super outbreak is one of the most infamous events that occurred in 1974. It was one of the most violent tornado events ever on record in the United States .The 1974 Super Outbreak spawned 148 tornadoes, the largest number of tornadoes ever produced by one storm system. Before the fourteenth state rampage was over 300 people had been killed in 48 killer tornadoes. On the morning of April 3, an area of low pressure was located in central Kansas. A warm front extended east northeastward through the lower Ohio River Valley. South of this front, extremely unstable air had gathered during the overnight hours and was rapidly spreading north. A cold front stretched from the area of low-pressure south through Texas. At the upper levels of the atmosphere, a powerful trough was spreading strong winds aloft over much of the eastern half of the country. With the warm air in place and a cold front approaching, along with the favorable upper air dynamics, intense thunderstorms developed rapidly in the afternoon of April 3.