Tornadoes in the United States Every state in the union has experienced them, and the destruction caused by tornadoes each year can climb into the billions of dollars. Scientists have learned a great deal about tornadoes over the past several decades, though, and warning systems are now able to prevent many of the casualties that tornadoes used to cause. To determine what has been learned and what steps have been taken for warning systems, this paper provides a review of the relevant peer-reviewed and scholarly literature concerning tornadoes, followed by a summary of the research and important findings in the conclusion.

Tornadoes are violently rotating columns of air that reach from a cloud to the earth's surface (What is a tornado?, 2014). The spring months of April, May, and June are the period in which the majority of tornadoes in the Northern Hemisphere are formed (Cavendish, 2000). During these months, the sun gradually but unequally warms the ocean and land surfaces following the cold of winter (Cavendish, 2005). Although they can occur, tornadoes do not typically occur in the Tropics because there is not as much seasonal variation in temperatures (Cavendish, 2005). Likewise, although they can occur in the cold polar regions and winter months anywhere, the more stable atmospheric conditions do not generally result in the formation of tornadoes (Cavendish, 2005). According to Cavendish, "Although tornadoes can appear anywhere and at any time of year, the United States experiences the largest number of anywhere in the...

A normal year will be marked with 600 to 1,000 tornadoes, with an average of 850 tornadoes per year; in 1973, a record 1,107 tornadoes hit the country" (2005, p. 1597). Although typically caused by thunderstorms, East Coast and Gulf Coast hurricanes and tropical storms are also responsible for generating numerous tornadoes (Moore & Dixon, 2011). For instance, during the period 1950 to 2005, 60 land-falling hurricanes along the Gulf coast alone produced 734 tornadoes (Moore & Dixon, 2011).
The United States has three distinct geographical regions that facilitate tornado formations. The first region, frequently called "Tornado Alley," runs from Texas through central Oklahoma, Kansas, Nebraska, and North and South Dakota (Cavendish, 2005). According to Cavendish, "During tornado season -- from April to June -- warm, moist air from the Gull of Mexico encounter cold, dry air from the Pole. This area tends to experience most of the strongest as well as the greatest number of tornadoes" (2005, p. 1597). Comparable geographic features over the southern Atlantic states and over the southern plains also produce tornado belts (Cavendish, 2005).

The National Weather Service (NWS) implemented the F-Scale in the early 1970s as the official tornado-intensity classification system and tornado reports prior to this year do not include tornado-intensity estimates (Moore & Dixon, 2011). In 1976, the National Severe Storms Forecast Center and the Nuclear Regulatory Commission reviewed and assigned F-Scale ratings…