It is a very common concept that we learn about in elementary school: tornado alley. Have you ever thought what actually went in to deciding what tornado alley was?
On March 20, 1948, two weather Air Force Officers took note of specific atmospheric conditions after a tornado tore through Tinker Air Force Base in the Oklahoma City suburbs. A few days later on March 25, 1948, the two noticed similar atmospheric conditions and issued the first tornado forecast.
A tornado touched down, and tornado forecasting was born in the United States. After their successful tornado forecast, the two weather officers began a research project on tornadic activity in Oklahoma and Texas, in an area they called tornado alley.
Tornado alley is an example of a vernacular region, meaning there is no officially defined tornado alley. Although, many Americans agree that tornado alley is made up of parts of Oklahoma, Texas, Kansas, and Nebraska.
Some may think that a tornado can only occur within tornado alley, but the area that sees the most tornadoes varies based on the season. In an effort to prove this, I took the path of all tornadoes from 1950 to 2020 and plotted them on a map of the United States. Then the tornadoes were plotted based on seasons and then a tornadic density, or the areas that see the most tornadoes, map was created.
Here is a map of the commonly defined tornado alley.
While looking at the maps of the four seasons, the one that most resembles this is meteorological spring. Tornadic density in meteorological spring is most dense in the classic tornado alley and portions of Arkansas, Louisiana, and Mississippi.
As temperatures rise during the summer, tornadic density moves north. The hot conditions in the deep south and midwest are not ideal for tornado development. The northern plains provide a better environment for tornadoes to develop.
As temperatures cool again into fall and winter, tornadic density moves to the deep south where there is still enough warm air and instability to produce tornadoes.
Although Missouri was not centered in any of the tornadic density maps, there can still be tornadoes. In fact, three of the top ten deadliest tornadoes occurred in Missouri.
Just because mid-Missouri is not in tornado alley, do not let your guard down during severe weather season. Tornadoes can happen anywhere.
