Why The U.S has so much tornadoes
Hollywood loves a really Good tornado. Like most things Hollywood it's all a little dramatic, but flying cows aside, there is something accurate about the setting as Dorothy in the Wizard of Oz said, "I have a feeling I'm not in Kansas anymore" you're not. However, the tornado started there, which makes sense. Tornadoes are far more common in the US than anywhere else. For perspective, Europe records around 300 tornadoes per year, whereas the US records well over a thousand. If we moved in a bit closer to the United States, you'd see that most of the world's tornadoes are happening in an area called Tornado Alley, which is a place that's perfect for twisters. Tornado Alley doesn't have any official boundaries, but it's typically considered this area that extends from northern Texas through Oklahoma, Kansas, Nebraska, Colorado, and South Dakota. Some people extend it even further east. While most states in the US have recorded at least one tornado, this area is a hot
bed, and the main reason for that is geography. The US's central part is unique because there's this extensive warm area of water just to the south and the vast high range of mountains that extend a long way from North to South. A tornado requires a couple of unique ingredients, ingredients that tornado alley is full of.
First, we would need a thunderstorm to make a thunderstorm. The things we need are warm moist air at low levels, Cold dry air above that, and some mechanism to lift that warm moist air. In tornado alley, lots of warm moist air flows into the Gulf of Mexico's plains and cold. Dry air flows from over the Rocky Mountains here in the west. Eventually, a temperature or pressure change will arrive and lift that warm-up air into the cold air forming an updraft. Once these two meet, the warm air's moisture begins to condense, forming clouds, and a thunderstorm starts. Under normal conditions, rain would fall from these clouds and cool the warm air breaking the storm, but there's a strong air current flowing from west to east known as the jet stream in tornado alley. This, Paired with the cold mountain air, blows the rain away, keeping the air in the updraft warm and wet, which allows the storm to the intensity and brings us to step two: getting the storm to rotate. To make that happen, we need winds moving at different speeds and directions.
As you can see, Tornado Alley has that in abundance. The air coming from the Gulf of Mexico moves slowly into the plains. Meanwhile, the jet stream from the mountains provides a steady stream of fast-moving high air flowing east. Because the jet stream is flowing faster and in different directions, causes the gulf below to rotate like a spinning football. When the spinning gets pulled into the updraft, it is tilted but continues to spin- causing the entire updraft to turn. Storms like this are known as "Supercells," and they create prime conditions for tornadoes.
They're rare but most commonly occur in tornado alley. As the supercell grows, the spiralling updraft begins to stretch towards the ground and forcefully pulls air into the cyclone. Air rushes in from the sides, and a spinning dust cloud forms below, which brings it to the final stage- getting the vertically spinning air to the ground. Phase three is the friction in the teacup. It's like using a spoon to swirl tea leaves at the bottom of a cup. The leaves rush into the center and are pulled up through the middle of the tea cyclone. In a real tornado, everything around the hurricane is sucked up- air, first. Debris, cows as more and more air is pulled in tightly, pressure builds, and the faster and longer tornado gets. It stretches closer to the ground until it eventually meets with the dust cloud. And then it touches down. We see most tornadoes in the central part of the US because of the ingredients necessary for a tornado to come together there more often. Sending any other place to the United States isn't the only place that gets tornadoes. Brazil in northern, eastern Argentina has some of the same ingredients tornado Alley does cold mountain air coming over the Andes and warm moist air coming from the amazon. But even still, the frequency of tornadoes is scored behind the US. Whole the right conditions come together; sometimes, the geography isn't exactly correct. In South America, the Andes aren't as wide as the Rockies, and the Amazon isn't as good of a moisture source as the Gulf of Mexico is because of its land. It's a goldilocks problem and a delicate recipe. Most people will go their entire lives without ever seeing a tornado, and some would consider that as lucky. Others actively seek them and those that start in Tornado alley, where the geography is just right.