A screenshot from a video of a tornado over the town of Millsap, Texas, taken by storm chaser Greg Kourounis on May 15, 2013.
Credit: Screenshot, gkourounis @YouTube
This article was provided by AccuWeather.com.
The United States is unique in the frequent amount of tornadoes it experiences yearly. However, it is not the only country that possesses the prime ingredients and topography to harness these often life-threatening storms. Tornadoes can occur in Northern South America, South Mexico, Northern Australia, Southern Asia and most of Africa.
"You can look at tornadoes like a family line. They start with a thunderstorm then require a change in wind veering and height to put a spin on the storm in the troposphere. That's the parent of a tornado, and it needs a very special environment to survive," AccuWeather Meteorologist Jim Andrews said.
However, it is widely agreed upon that more than one location on the globe contains the selective environment to produce these violent storms. Besides areas in North America, South America, particularly Argentina and Brazil, receive a great deal of hail and tornadoes annually.
"Internationally, we don't have a lot of data or reporting services, so it's difficult to say where the tornado alleys are internationally but if you look in a region of Córdoba, Argentina, down towards Buenos Aires and in Santa Catarina, Brazil, that's where the most tornadic storms happen. It's where we can see the biggest hail and where the most frequent hail falls on the planet and with that big hail you're likely to get a large number of tornadoes," Harold Brooks, senior scientist of Forecast Research and Development Division for NOAA, said.
Comparing tornado frequency of South America to that of North America, there are similarities but the differences lie in how the tornadoes form in the two very different locations. For example, the infamous "tornado alley" gets a large source of its moisture from the Gulf of Mexico, whereas other locations pull much-needed moisture from a number of different sources.
"You bring air over the Andes and the drawback you have there is that the Andes are taller than the Rockies. They're [the Andes] not as wide so the air doesn't spend as much time over that range of mountains. The Amazon is a source of moisture and even though it's really moist, it's not nearly as good as having a body of water near it [like the Gulf of Mexico in the United States Great Plains, for example]," Brooks said.
North America, including southern Canada, receives its moisture, a key ingredient to producing tornadoes, from the Gulf of Mexico as well.
"The Canadian experience is essentially an extended U.S. experience. It does take a lot longer for them to get moisture up from the Gulf of Mexico and as you go further along into their growing season, there is a lot of recycling of water vapor from plants so you end up getting a lot of moisture," Brooks said.
Another international region to consider is the Indian Subcontinent, which is often associated with a monsoon season but not tornadoes. Andrews said tornadoes do not happen frequently here, but when they do strike, they are very severe.
"Winters in this region are typically dry, the weather quite literally springs to life in the warmer months and it tends to become a very moist flow over the Bay of Bengal. If a very weak cold front were to move along the jet stream, it could produce some very severe weather," Andrews said.
Areas near the mountain ranges that experience colder air yet are close enough to a source of moisture will see tornadoes.
"We have tornadoes near Bangladesh and in the vicinity of the Himalayas," Brooks said.
According to the AccuWeather almanac, in 1969, the city of Dhaka, India, experienced violent storms with estimated 90-mph wind gusts and the world's heaviest hail storm to date. Pieces of hail were found in Gopalganj, India, weighing in at 2.25 pounds; 540 people were killed in Bangladesh.
Tornadoes often favor a large region of flat lands. The Bhubaneswar region of India, a flat river delta, is a prime location for a tornado to form. Mountains aren't bad for tornadoes, but they typically don't like to happen there, Andrews said, which is why areas like Australia may not get as many tornadoes.
"Australia is limited by the fact that the area east of the Great Dividing Range and the Range itself aren't very high like the Rockies. The area west isn't very big so there is not much room to make storms or tornadoes. You're essentially saying, 'What would happen to storms in the U.S., if the Colorado-Kansas border was suddenly ocean?' The answer would be that there wouldn't be a whole lot of room in order to make storms and that's the same limitation in Australia," Brooks said.
Sharing similar qualities in landscape to Australia, there are parts of even South Africa that resemble the popular region deemed as "tornado alley," in the United States.
"Southeastern South Africa, most of which is a plateau [The Drakensberg Plateau], is about 1,500 meters above sea level. There is a small coastal region at sea level from Durban down toward Port Elizabeth that is the kind of place in South Africa that has the same kind of setup as Australia does. Except instead of a mountain range, it's kind of a nice sort of flat area that everything falls off which in some sense resembles eastern New Mexico or West Texas," Brooks said.
European countries such as France and Italy are no exception either, Andrews said.
"France has been known to have quite a few tornadoes as well as Italy. One in particular comes to mind, in Taranto, Italy, in 2012, where it completely destroyed a steel plant and left a lot of people injured. People often forget that Italy is a very stormy place, especially in the spring and fall. It's no tornado alley, but it has its moments," Andrews said.
There is research both for and against the multiple locations in the United States where conditions are prime to nurture a tornado. There are also several international locations that can claim the same.
"[Tornadoes] can happen just about anywhere if the conditions are just right," Brooks said.