[1] The term was first used in 1952 as the title of a research project to study severe weather in areas of Texas, Louisiana, Oklahoma, Kansas, South Dakota, Iowa and Nebraska.
[3] As a colloquial term there are no definitively set boundaries of Tornado Alley, but the area common to most definitions extends from Texas, through Oklahoma, Kansas, Nebraska, South Dakota, Iowa, Minnesota, Wisconsin, Illinois, Indiana, Missouri, Arkansas, North Dakota, Montana, Ohio, and eastern portions of Colorado, New Mexico and Wyoming.
[15] Tornado Alley can also be defined as an area reaching from central Texas to the Canadian Prairies and from eastern Colorado to western Ohio.
[5] A coherent conception considers that there is a single Tornado Alley in the United States and Canada, and that this can simply be subdivided into smaller areas based on regional attributes.
[18] The term "tornado alley" was first used in 1952 by U.S. Air Force meteorologists Major Ernest J. Fawbush (1915–1982) and Captain Robert C. Miller (1920–1998), as the title of a research project[19] to study severe weather in parts of Texas and Oklahoma.
Much of the housing in this region is less robust compared to other areas in the United States, and many people live in mobile homes.
[citation needed] These figures, reported by the National Climatic Data Center for the period between 1991 and 2010, show the seventeen U.S. states with the highest average number of EF0-EF5 tornadoes per 10,000 square miles (25,899.9 km2) per year.
[citation needed] The average number of tornadoes per equal area of land is highest in the southern parts of Alberta, Saskatchewan, Manitoba, and Ontario.
[24] Another third of Canadian tornadoes strike Southern Ontario and Quebec, especially in the region between the Great Lakes and the nation's capital city, Ottawa.
In more recent years, an emerging trend has suggested that the Ottawa Valley is seeing an increasing number of frequent and violent tornadoes.
[citation needed] Southwestern Ontario weather is strongly influenced by its peninsular position between the Great Lakes.