To start, one may ask: "Where is Tornado Alley, and do I actually live in this area?"
This is a question that could be answered or portrayed a few different ways. Many outlined areas, or small differences can be displayed in different maps, outlooks, etc. However, there are actually two different Tornado Alley's in the field of weather study. The term "Tornado Alley" was first used in 1952 by U.S. Air Force meteorologists Major Ernest J. Fawbush, and Captain Robert C. Miller. The phrase was coined as the title of a research project to study severe weather in parts of Texas and Oklahoma.
Traditional Tornado Alley is often viewed as the central plains of the United States. Far eastern New Mexico, eastern Colorado, portions of Minnesota, portions of Iowa, western Missouri, and a large chunk of Texas is also included. Yes, tornadoes can and do occur outside of Tornado Alley. However, tornado alley is defined as: "an area of the Great Plains centered through Kansas and Oklahoma and including parts of the surrounding states, where tornadoes are FREQUENT".
You didn't think we forgot about Arkansas did you? Remember, we stated there are two areas viewed as Tornado Alley. Dixie Alley is a large area circled throughout the southeast portion of the United States. Alabama, Arkansas, Mississippi, Louisiana, Tennessee, Georgia, and small portions of North Carolina and Kentucky are included.
One could argue that these defined areas are rather vague. Tornadoes, some deadly, occur in different parts of the United States. However, over history the areas in the two Tornado Alley's have been known to frequent large, destructive, and even deadly tornadoes.
When you view a map such as this highlighted map showing the history of tornado watches in the years spanning from 1993-2012, it brings to life the true nature of living in Tornado Alley. Notice the brighter shades of pink in the areas of Dixie Alley, and the southern portions of Traditional Tornado Alley.
The reasoning behind these areas being exposed to an elevated tornado threat involves several key components.
One major key component involves the Gulf of Mexico, the gulf allows warm moist air masses to rise north. With these warmer humid air masses, the jet stream aloft is set on a collision course with this air mass. Along with the jet stream, cooler air from the northern continental US and drier air from the desert southwest aids in storm development.
The United States averages a staggering 1,200 tornadoes per year, more than any other country by far. Below is a numerical list portraying the states with the highest average number of tornadoes per 10,000 square miles or 26,000 km. This data has been accounted for ranging from the years of 1991-2010 (courtesy of the National Climatic Data Center). Notice the state of Florida is #1, this stems from tropical weather including stronger Hurricanes. In reference to that statistic, that will be explained in a further blog.
1. Florida: 12.2
2. Kansas: 11.7
3. Maryland: 9.9
4. Illinois: 9.7
5. Mississippi: 9.2
6. Iowa: 9.1
7. Oklahoma: 9
8. South Carolina: 9
9. Alabama: 8.6
10. Louisiana: 8.5
11. Arkansas: 7.5
12. Nebraska: 7.4
13. Missouri: 6.5
14. North Carolina: 6.4
15. Tennessee: 6.2
16. Indiana: 6.1
17. Texas: 5.9
We hope you enjoyed this blog, and have learned something new today! We will have a blog posted next week regarding another aspect of severe weather.
-AW Team
