Within the U.S., each state has had at least one tornado, and some have dozens each year.
The US is special about producing so many tornadoes, especially violent ones.
Texas has an average of 140 tornadoes each year – the most of any state. Kansas, Florida, Oklahoma and Nebraska exclude the top five.
But the total number of tornadoes does not always tell the whole story. For example, despite the fact that Alabama has an average of 42 tornadoes a year – more than three times less as Texas – this is at the top of the list for tornado deaths.
The time of day and the topography where the tornado occurs make a big difference in the mortality rate.
The topography in Alabama and other southern states often contains rolling hills, plateaus, and many more trees than the plains states such as Kansas, Texas, and Nebraska, where a tornado can often be seen miles away. The more likely a tornado is to be seen often results in faster reporting, which provides more time for people to be alerted and seek shelter.
Southern states like Tennessee, Kentucky and Arkansas also see more tornadoes overnight compared to any other state. This can lead to higher deaths because many people sleep and do not know that a tornado is approaching.
“Tornadoes in the southeast tend to be more dangerous than their counterparts in Great Plains,” said Brandon Miller, CNN meteorologist. “There are a number of reasons for this, some weather and geographical. Southeast tornadoes often travel faster, moving through a faster jet stream.”
All of these factors can lead to a higher mortality rate in southern states compared to the plains. But all these states have a few things in common: the ideal atmospheric conditions for the formation of tornadoes.
‘The basic ingredients for severe thunderstorms that can cause tornadoes are warm, humid air near the ground, relatively dry, cool air upward (about 10,000 to 30,000 feet) and horizontal winds in the area that form the storm, which increases as you go the ground up and down changes with altitude, blowing from the equator near the ground and up from the west, “says Dr. Harold Brooks, senior scientist at the NOAA National Laboratory for Severe Storms.
Low pressure systems in the US draw warm, moist air from the Gulf of Mexico and cool, dry air up from the Rocky Mountains or the High Desert in the southwest. The states that fall between these two regions are ultimately the ideal place to catch fire under heavy weather.
“No other place in the world has the great warm water on its equator, with a wide variety of mountains stretching from north to south to the west of it,” said Dr. Brooks said. “All the other regions that are prone to tornadoes have at least one function that is not optimal.”
The US leads every other country for tornadoes
Other countries are experiencing tornadoes, including Germany, Australia, South Africa, eastern China, Japan, Bangladesh, Argentina and more.
Europe as a whole is comparable to the size of the US, but there is a big difference in the number of tornadoes and tornado deaths.
From 2011 to 2020, the US averaged 1,173 tornadoes per year and Europe about 256. However, Pieter Groenemeijer, director of the European Laboratory for Severe Storms (ESSL), warns that the European number could be low.
“Weak tornadoes are likely to be under-reported in some countries, such as France and the United Kingdom,” Groenemeijer said.
European Russia (which is part of the country west of a longitude of 58 degrees East), is at the top of 86 tornadoes annually. Germany comes in second annually with an average of 28 tornadoes.
The study also reports that thunderstorms occur twice as frequently in the United States, with as many as four times more storm reports, compared to Europe.
Southern Hemisphere tornadoes usually rotate clockwise, which is the opposite of how northern hemisphere tornadoes rotate.
