The US average is over 1,150 tornadoes per year. That’s more than any other country. In fact, it’s more than Canada, Australia and all European countries combined.
Within the US, every state has had at least one tornado, and some have dozens each year. The US is special in terms of producing so many tornadoes, especially violent ones.
+ Tornadoes in the southern US leave one dead and several missing
In the United States, the average number of deaths from tornadoes per year is 73. But in Europe, where tornadoes are generally much weaker, deaths are estimated at between 10 and 15 annually.
Some states are deadlier than others
Texas averages 140 tornadoes a year — more than any other state. Kansas, Florida, Oklahoma and Nebraska round out the top five.
But the total number of tornadoes doesn’t always tell the whole story. For example, even though Alabama averages 42 tornadoes a year — more than three times fewer than Texas — it tops the list of fatal tornado victims.
Alabama averages 14 tornado deaths per year, nearly twice as many as second-largest Missouri, with eight deaths per year.
The time of day and the topography where the tornado occurs make a big difference in the death rate.
The topography in Alabama and other southern states generally includes hills, plateaus, and many more trees than in plains states like Kansas, Texas, and Nebraska, where a tornado can be seen for miles. The more likely a tornado can be seen often leads to the tornado being reported more quickly, allowing more time for people to be warned and seek shelter.
Southern states like Tennessee, Kentucky and Arkansas also see more tornadoes at night than any other state. This can lead to greater fatalities, as many people are sleeping and unaware that a tornado is approaching.
“Tornadoes in the southeast tend to be more dangerous than those in the Great Plains,” says Brandon Miller, a meteorologist for CNN. “There are a number of reasons for this, some climatic and some geographic. Southeast tornadoes generally travel faster, powered by a faster jet stream.”
All these factors can lead to a higher death rate in the southern states compared to the plains. But all these states have a few things in common: the ideal atmospheric conditions for tornadoes to form.
“The basic ingredients for severe storms that can produce tornadoes are warm, moist air close to the ground, relatively dry, cold air aloft (about 10,000 to 30,000 feet), and horizontal winds in the environment in which the storm forms that increase as the storm forms. that you move from the ground upwards and change direction with height, blowing from the equator near the ground and from the west at the top,” says Dr. Harold Brooks, senior scientist at NOAA’s National Severe Storms Laboratory.
Low pressure systems in the United States draw warm, moist air from the Gulf of Mexico and cold, dry air from the Rocky Mountains or the High Desert in the southwest. The states that lie between these two regions turn out to be the ideal place for the onset of severe weather.
“Nowhere else in the world has the big warm water on its equatorial side with a big mountain range running north to south west of it,” Brooks said. “Every other tornado-prone region has at least one less-than-ideal feature.”
The US leads all other countries in tornadoes
Other countries experience tornadoes including Germany, Australia, South Africa, East China, Japan, Bangladesh, Argentina and more.
Europe as a whole is comparable in size to the United States, but there is a big difference in the number of tornadoes and deaths caused by tornadoes.
From 2011 to 2020, the US averaged a preliminary total of 1,173 tornadoes per year, and Europe around 256. However, Dr. Pieter Groenemeijer, director of the European Severe Storms Laboratory (ESSL), cautions that the European figure could be low. side.
“It is likely that weaker tornadoes are still underreported in some countries, such as France and the United Kingdom,” says Groenemeijer.
European Russia (which is the part of the country west of 58 degrees east longitude) tops the list with 86 tornadoes annually. Germany comes in second with an average of 28 tornadoes annually.
The peak density of tornado reports coincides with high population density in Belgium, the Netherlands and northern Germany, according to a study of severe storms in Europe published in December 2020.
The study also reports that storms are twice as frequent in the United States, with up to four times as many storm reports, compared to Europe.
One thing that most countries have in common is the time of day that tornadoes occur, which is most frequent in the afternoon and early evening. But high season is not the same. In the US, spring is the peak of tornado activity. For central and northern Europe, the main tornado season is summer, while it is autumn for the western and central Mediterranean and winter in the eastern Mediterranean.
Outside of the US, Canada ranks second on the list for most tornadoes, with an average of 100 per year.
Tornadoes are not limited to the Northern Hemisphere. Australia has dozens every year, and South Africa also reports annual occurrences. South America, like other continents, has its own tornado hotspot known as “passillo de los tornadoes”. This tornado corridor includes Argentina, Uruguay, Paraguay and a part of Brazil.
According to New Zealand’s National Institute of Water and Atmospheric Research, tornadoes are relatively rare there. On average, around seven to ten moderate to strong tornado events are reported in New Zealand every year.
Tornadoes from the Southern Hemisphere generally rotate clockwise, which is the opposite of how tornadoes mostly rotate in the Northern Hemisphere.
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