Tornado in Wray, Colorado

Tornado Alley

Tornado Alley refers to a region in the central United States frequented by tornadoes. In this area, a tornado occurs when the moist air from the Gulf of Mexico meets the dry cold air from Canada. Although the area described as Tornado Alley has no defined boundary, it includes the Great Plain states like Texas, Kansas, Oklahoma, Iowa, Nebraska, and South Dakota.  Other states that are sometimes included as part of the tornado region include Ohio, North Dakota, Arkansas, Montana, and Indiana, etc. Although the region experiences tornados throughout the year, most occur in the summer and spring months and are often accompanied by thunderstorms.

Where Is Tornado Alley?

Tornado Alley
Damage caused by a tornado in Louisiana.

Several regions in the US are prone to tornado watches, including Gulf Coast, Southern Plains, Upper Midwest, and Northern Plains. However, almost all states experience tornadoes, though the wind storms are frequent in the central United States, between the Appalachian and the Rocky Mountains. The term “Tornado Alley” was invented by Captain Robert Miller and Major Ernest Fawbush, who included it in a 1952 research project that studied the severe weather in Oklahoma and Texas. Although the term refers to an area in the central United States that experiences frequent tornadoes, the National Weather Service is yet to designate it as an official definition. Therefore, different locations and regions are always included as part of the Tornado Alley.

Although the boundaries for the Tornado Alley differ from source to source, it encompasses the Great Plain states of Louisiana, Texas, Iowa, Kansas, South Dakota, Oklahoma, and Nebraska. Some sources include states like Illinois, Wisconsin, Indiana, western Ohio, and Minnesota as part of Tornado Alley. Tornado Alley can also be defined as the area with frequent strongest tornadoes. Some sources also suggest that there are several Tornado Alleys besides Texas to Kansas region. These alleys may include Upper Midwest, the lower Mississippi, Tennessee, and Ohio valleys.

Why Tornadoes Frequent Tornado Alley?

Tornadoes in Tornado Alley
Damage caused by a tornado in Tornado Alley area.

Tornado outbreaks are common across the United States due to the increasingly warm weather. Tornadoes can form in any location within the country and the entire North American continent, with the US experiencing about 1,200 such violent wind storms annually. However, the Tornado Alley is one of the most affected areas by tornadoes because most of the conditions required for the wind storms to form prevail in the area. The region, which is part of the Great Plains, has a flat and dry terrain and is a perfect place where competing air masses meet. Warm air rising from the Gulf of Mexico meets the cool, dry wind from the Rockies. When these competing sets of air masses meet, the cold, dry air sinks, and the warm, moist wind rises, causing a violent storm.

Frequency Of Tornados

Tornado in Kansas
Tornado in Rozel city of Kansas.

Texas experiences the highest number of tornadoes due to its size and location on the region’s southern end. However, Kansas reported the most tornadoes per area in 2007, followed by Oklahoma. Although Florida reported frequent tornadoes in 2013, the windstorms were not as strong as those experienced in Southern Plains. Florida experienced an average of 12.2 tornadoes per 25,900 square kilometers annually between 1991 and 2010, making it the state with the highest number of tornadoes per area during that period, followed by Kansas (11.7) and Maryland (9.9). Texas recorded 5.9 tornadoes per the unit area per year in the same period.


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