The United States experiences approximately 75 percent of the world’s known tornadoes and thus is notorious for its tornado climatology in terms of frequency, intensity, and destructive outbreak events. While it is appropriate to focus on tornadoes across the United States, it is important to recognize that tornadoes also happen in other countries of the world.
This article investigates where many of the other 25 percent of the world’s tornadoes occur, with a specific emphasis on our North American neighbors of Canada and Mexico. How do other countries match up against the United States when it comes to tornado climatology? You’re about to find out. (Hint: The U.S. is the uncontested heavy weight champion of the world.)
This may serve as a bit of a surprise, but Canada is actually number two behind the United States for total annual frequency of tornadoes, with a whopping 5 percent of the globe’s total! While not intuitive at first, given Canada is often associated with a cold and rural landscape, it actually experiences a fairly robust tornado season from middle to late summer — typically mid-June through the month of July and into August.
If you’re familiar with the monthly tornado climatology of the United States, you can recognize that tornadoes are focused in the South during the winter, near the Gulf of Mexico’s warmth, then travel northward as the warm season arrives. Tornado activity often reaches peak in the central plains of Oklahoma and Kansas by late May and early June, eventually reaching the Dakotas by mid-June into July.
While we tend to dismiss what happens after that here in the United States, that northward trend in tornado occurrence continues into southern Canada through late summer. The Canadian Plains and Prairies, particularly encompassing the southern areas of Alberta, Saskatchewan and Manitoba, are much like the U.S. Great Plains, with flat and open terrain prone to clashes of Gulf of Mexico air and colder arctic air. Ontario and Quebec is another active tornado region in the country.
On average, Canada experiences approximately 60 to 100 confirmed* tornadoes a year, with the majority in the F/EF0-F/EF2 range. (*Disclaimer: some tornadoes likely go unreported since the majority occur over the vast and unpopulated areas of the Canadian open Prairies.)
An interesting note is that the tornado fatality rate tends to be lower in Canada than in the United States. An obvious reason for this is that lower population centers are in the path of most tornadoes, but another reason is that houses are often built stronger in order to endure the extreme winter weather conditions. Canada also tends to see fewer of the most extreme tornadoes, though the equivalent to an F5/EF5 event has been recorded there.
Unlike Canada, the U.S. neighbor to the south does not have as impressive of a tornado history. Dominated by a moist and tropical air mass near the coasts and an arid one inland, Mexico is simply at too far of southern latitude for cold intrusions from the north that cause the temperature clash needed to produce numerous tornadic thunderstorms. With paltry reports of confirmed tornadoes and really no fatality records, there is not much of a tornado climatology for the country of Mexico.
One interesting fact, however, is that Mexico claims the first tornado ever reported for North America, called the “Tenochtitlan-Tlatelolco tornado” which occurred on August 13, 1521. It is likely that places just south of the border of far south Texas have a similar tornado climatology to that region, but even the U.S. side does not see as frequent activity as spots further north in the state. Tropical systems are also likely a cause of some tornadoes in Mexico.
When it comes to the continents, North America is the powerhouse for tornado climatology. The United States and Canada combined boasts 80 percent of the world’s tornadoes. That leaves the remaining 20 percent to be distributed across dozens of different countries, including those in continental Europe, as well as Bangladesh, South Africa, Australia, and Argentina among others.
…Selected highlights across the world…
If Europe was one country, it would take Canada’s second place spot when it comes to tornado production per year. Scientists in the region have said that up to 300 tornadoes per year touch down across the continent, though a good deal less are usually reported.
Russia, while not entirely (or mostly!) in Europe, is the likely leader of tornadoes per year in the region due to its massive size. Influenced by contrasting air masses courtesy of the Gobi Desert and the Himalayan Mountains, tornadoes can be quite prevalent across the large country. Most tornadoes there are weak and go largely unreported. The western/European part of the country is home to the most reports, but this may be population biased.
The United Kingdom is believed to lead the pack in non-Russia Europe, with over 30 tornadoes per year, again largely of the weak variety. Germany, while boasting a lower average with just 10 per year, appears to be near the heart of Europe’s stronger tornado alley, which generally runs from northeast France toward Poland. Tornado frequency is also relatively high in many areas along the Mediterranean Sea.
Because they are not terribly common in any one place, Europe does not tend to face high impact tornado events. The deadliest tornadoes in European history are both believed to have started as waterspouts. One in Malta killed upwards of 600 people in a shipping armada (1551), and another was described as twin waterspouts which became violent tornadoes near Sicily (1851), killing upwards of 500. Both of these incidents are so far in the past that it is difficult to ascertain their historical accuracy.
Bangladesh has a well-known and destructive tornado history, and currently sits at number three as the country with the most reported tornadoes behind the U.S. and Canada. Not only is this country known for violent tornado outbreaks, it is also known for an incredibly high tornado fatality rate. In contrast to Canada, Bangladesh is one of the most populated countries in the world, putting many people in harm’s way of these destructive storms. Also, a country ridden by poverty, the majority of structures are not built to withstand tornadic winds. In fact, fatality rates of 30 or more per each tornado event are not uncommon even at present day.
The prevalence of tornadoes across Bangladesh all has to do with geography. South of the country is the large Bay of Bengal, which is a warm and humid body of water similar to the Gulf of Mexico (due to the influence of the Bay of Bengal, locals actually call the tornadoes “Bengal tornadoes.”). Take the warmth and moisture from the Sea of Bengal and couple that with the cold and dry air streaming south from the Himalayas and Tibetan Plateau to the north, and you’ve got the temperature/humidity clash needed to fuel tornadic storms. This clash is especially common during the Indian Monsoon season.
Unfortunately, Bangladesh also holds the record for single deadliest tornado. It occurred on April 26th, 1989 killing 1,300 people.
For more information on the tornado climatology for Bangladesh check out this site: http://bangladeshtornadoes.org/
Researching Australian tornadoes, there were multiple articles stating that many people believe “tornadoes don’t happen in Australia.” While this is a myth, many meteorologists believe under-reporting due to desolate and low-populated areas is a major reason for the belief that tornadoes do not happen across Australia. On average, 20 to 25 tornadoes are reported in the country per year.
There is one major difference between Australian climatology when compared to the previously mentioned countries: Australia is not situated in the middle latitudes, meaning it does not experience a clash in different air masses and thus temperatures needed to frequently produce tornadic supercell thunderstorms. Instead, the vast majority of the tornadoes are caused by land-falling tropical cyclones, especially in the southeastern part of the country. New Zealand also sees a number of tornadoes each year.
Argentina does not necessarily have a high annual average of tornadoes, but it does have a history of experiencing the strongest tornadoes in the southern hemisphere, and density of tornado reports is considerable. When all Argentinian recorded tornadoes are taken into account, the ratio of strong tornadoes (F/EF3-F/EF5 range) to weak tornadoes is higher than ratios elsewhere in the world (excluding the U.S.). In fact, the strongest tornado in the southern hemisphere on record occurred in the Sante Fe Province of Argentina (called the San Justo tornado) on January 10, 1973. This tornado had estimated winds equivalent to F5 intensity.
While there is not much other information readily available regarding tornado climatology for Argentina, it is believed that the Andes Mountains play an important role in influencing the air mass interactions and wind dynamics, priming an atmosphere conducive for tornado development.
The South African Weather Service reports that tornadoes occur all over the country, but surprisingly the highest concentration of confirmed tornadoes occurs in the mountainous region of the Free State of Gauteng. They report that 90 percent of their tornadoes are classified as F/EF 0-F/EF2, and most of the tornadoes occur during their spring and summer months, between October and February.
While the United States holds the gold medal when it comes to total number of tornadoes both on average annually and for overall total (recorded history), it is important to recognize that tornadoes do happen elsewhere around the world. The United States may have the most impressive climatology in terms of number, frequency, and intensity but other countries such as Bangladesh, Australia, and Argentina likewise boast impressive tornado histories.
Other countries not covered in detail, including Japan and China, are also home to at least a handful of tornadoes per year. In fact, even in places not highlighted on the world map, few are totally immune to their occurrence.
Bottom line: Not only is the Great Plains region the tornado alley of the United States, it’s the tornado alley of the world.
Ian Livingston contributed to this post.
A review of worldwide tornadoes, A.M. Goligher and R.V. Milford
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