Every year the American Midwest states get pummeled by tornadoes. If it feels like the United States has more tornadoes than the rest of the world combined, you might be right. However, the answer is a bit more complicated. But why are there so many tornadoes in the United States? And if there are more tornadoes there than everywhere else in the world, how many is that?
The United States has experienced at least 1,000 tornadoes every year since 1990. On average, there are around 1,200 tornadoes every year. That’s a lot of wind! Most tornadoes don’t land in populated areas or last long enough to cause much damage. Those that do usually make the headlines. If you’ve ever sat and thought about why there are so many tornadoes in the Midwest, you’re not alone. Here’s why.
Why Does the United States Have so Many Tornadoes?
Tornadoes usually form in storms known as super-cells. These unique storm formations suck warm, wet air from lower altitudes, and cold, dry air rushes down to replace it. This cycle causes the air to rotate rapidly. If it rotates quickly and tightly enough, a self-sustaining cyclone will appear. The tornado itself is actually invisible, and it is the debris and moisture in the air that makes the outer wind wall visible to us.
This mixture of hot, wet air, and cold dry air, usually needs a flat area for the wind to move freely. Tall mountains and other geographic features that will change or obstruct the flow of wind and humidity will impact the formation of tornadoes.
A combination of the United States’ unique topology and location makes for a perfect recipe for cooking up tornadoes. Winds from the Southeast bring hot, wet air from the Gulf of Mexico into the United States. On the other side, winds from the West rain their moisture over the Rocky Mountains before entering the Midwest as cold, dry air. Cold air from Canada also joins the party. These streams usually form powerful fronts that meet over the Great Plains and Mississippi River Valley. The Great Plains heat up very quickly during the spring and summer, creating large pockets of rising hot air. This makes the Midwest a paradise for tornado hunters.
The storm fronts that combine to create tornadoes occur regularly in this part of the world. They are a common occurrence and are unobstructed by mountains or large bodies of water. It is more likely, therefore, that they would meet and form tornadoes. The tornadoes that form here can run for miles and miles before the storms lose too much energy to sustain the tornado.
This process of hot and cold weather fronts meeting and forming tornadoes is so predictable, in fact, that storm chasers are able to anticipate when and where tornadoes will touch down with surprising accuracy.
This combination of unique geography and weather has earned this part of the United States the nickname Tornado Alley.
Does the U.S. Actually Have More Tornadoes Than The Rest of The World Combined?
Yes and… maybe.
The United States does have more tornadoes than any other country. This is true. Canada has the second-highest number of annual tornadoes at just 100 per year! It’s safe the say the competition is not close.
But does it have more than the rest of the world combined? That is hard to say. While we know that the United States has a lot of tornadoes, scientists can’t confirm whether or not the amount is higher than the rest of the world. This is because the data from the rest of the world is incomplete and may be skewed.
They can say, though, that the number of tornadoes that happen every year is likely higher than what is being reported.
The United States has a high number of tornadoes every year because it is a perfect place for tornadoes to form, but also because these tornadoes touch down in highly-populated areas with a strong culture of tornado chasers. Tornadoes do happen a lot in other countries, but they usually touch down in remote or unpopulated areas.
Australia, Russia, and Brazil all report a few tornadoes every year, but these are usually only those that impact populated places. They do not keep records of every tornado that forms. These counties are incredibly massive, with large swaths of wilderness in their centers where tornadoes form and disappear without anyone ever knowing. Australia, for example, reports around 20 tornadoes every year, but experts believe the number is much higher.
Russia comes in second place with around 86 tornadoes reported every year. Germany has around 28 each year. Europe as a whole only has about 250 tornado reports annually.
Other large, flat areas, like Africa and the Middle East, probably experience many tornadoes, but they are not recorded. New Zealand reports around 10 tornadoes each year. South America has its own “tornado corridor” that covers Argentina, Uruguay, Brazil, and Paraguay.
Why Don’t Other Countries Have as Many Tornadoes?
The ingredients for tornado formation are hot, wet air at low altitudes, cool, dry air and high altitudes, and large open areas. In almost every other part of the world where geography provides these ingredients, they are combined sub-optimally, irregularly, or only partially.
So, does the United States have more tornadoes than the rest of the world combined? Yes, if we compare the data we have. If every country in the world, however, kept records of every tornado that formed, the competition might be much closer.
The photo featured at the top of this post is © Rasica/Shutterstock.com
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