Tornadoes form in a thunderstorm called supercells. These storms must have a low level of moisture. Then, for a tornado to form, a cold front must meet a warm front. The warm front then will rise. Winds in distinct elevations must be blowing in different direction, speed or both, creating a horizontal spinning effect. When the faster the wind, the faster the rotation. Another condition for a tornado to form is a ¨trigger,¨ such as a cold front or other level converging winds.
The deadliest tornado in U.S. history is the Tri-State Tornado. This tornado traveled over 300 miles through eastern Missouri, southern Illinois, and southern Indiana. The disaster took place on March 18, 1925 at 1:00 in the afternoon and lasted for about three and a half hours. Winds gusts blew 260 mph and over. The tornado totally destroyed numbers of towns, costing millions of dollars, also killing 695 and injuring 2,027 people. The Tri-State Tornado was rated F-5, the most powerful tornado yet.
Moore, Oklahoma 2013
The Moore, Oklahoma tornado of 2013 was the most deadly tornado of the year. Severe storms began on May 18, 2013 and lasted into May 20. Then, in the early afternoon of May 20, many supercell storms started to develop in the dry line of Oklahoma. Finally at 2:56 pm, a massive tornado formed. With a rating of EF-5 (the most powerful), wind speeds blew over 200 mph. The tornado destroyed everything in its path, including school buildings, businesses and many homes. This disaster was estimated to cost $2 billion. 24 were killed, and 377 people were injured. The tornado path was about 14 miles long and 1.1 miles wide. This tornado was on the ground for 40 minutes, ending at 3:35 pm.
Impact on Human Life
Tornadoes cause many problems for human life. Where tornadoes happen the most, homes and buildings have basements, cellars, interior rooms, or lower rooms with little/no windows. Tornadoes destroy lots of property, costing hundreds for the economy. Cities and news channels have tornado watches, warnings, and sirens. Some tornado signs people watch for are: dark greenish clouds, funnel clouds, large hail, and loud, roaring noises.