Why the US is the ideal breeding ground for tornadoes

Why the US is the ideal breeding ground for tornadoes

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In the United States, each state has had at least one tornado, and some have dozens each year.

The United States is special in terms of producing so many tornadoes, especially the violent ones.

Texas has an average of 140 tornadoes every year – the largest of any state. Kansas, Florida, Oklahoma and Nebraska complete the top five.

But the total number of tornadoes doesn’t always tell the whole story. For example, although Alabama averages 42 tornadoes a year – more than three times any less than Texas – tops the list of tornado fatalities.

Alabama averages 14 tornado deaths per year, almost double the next number – Missouri, with eight deaths per year.

The time of day and the topography where the tornado occurs make a big difference in the mortality rate.

The topography of Alabama and other southern states generally includes hills, plateaus and many more trees than the lowland states like Kansas, Texas and Nebraska, where a tornado can be seen miles away. The greater the likelihood of a tornado being seen, it generally leads to faster reporting of the tornado, 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 a greater number of fatalities, as many people are asleep and are unaware that a tornado is approaching.

“Tornadoes in the Southeast tend to be more dangerous than their Great Plains counterparts,” said Brandon Miller, a CNN meteorologist. “There are a number of reasons for this, some weather and some geographic. Southeast tornadoes tend to travel faster, driven by a faster jet stream.”

All of these factors can lead to a higher fatality rate in the southern states compared to the plains. But all of these states have some things in common: the ideal atmospheric conditions for the formation of tornadoes.

“The basic ingredients for severe storms that can cause tornadoes are hot and humid air near the ground, relatively dry and cold air overhead (about 10,000 to 30,000 feet) and horizontal winds in the environment in which the storm forms and increases as you go. the soil goes up and changes direction with height, blowing from the equator close to the ground and from the west at the top “, says Dr. Harold Brooks, senior scientist at NOAA’s National Laboratory for Severe Storms.

Low-pressure systems in the U.S. draw warm, humid air from the Gulf of Mexico and cold, dry air from the Rocky Mountains or the High Desert in the southwest. The states located between these two regions end up being the ideal place for the onset of bad weather.

“No other place in the world has great warm waters on its side of the equator, with a wide range of mountains stretching from north to south to west of it,” said Brooks. “All other tornado-prone regions have at least one sub-ideal feature.”

The USA leads all other countries in tornadoes

Other countries are experiencing tornadoes, including Germany, Australia, South Africa, eastern China, Japan, Bangladesh, Argentina and more.

Europe as a whole is comparable to the size of the USA, but there is a big difference in the number of tornadoes and fatalities.

From 2011 to 2020, the USA averaged a preliminary total of 1,173 tornadoes per year and Europe about 256. However, Dr. Pieter Groenemeijer, Director of the European Severe Storms Laboratory (ESSL), warns that the European number may be low lateral.

“Weaker tornadoes are probably still underreported in some countries, such as France and the United Kingdom,” said Groenemeijer.

European Russia (which is the part of the country 58 degrees east longitude) leads the list with 86 tornadoes a year. Germany comes in second, with an average of 28 tornados per year.

The peak density of tornado reports coincides with the high population density in Belgium, the Netherlands and northern Germany, according to a study on 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 reports of storms as compared to Europe.

One thing that most countries have in common is the time of day that tornadoes occur, which occurs most often in the afternoon and early evening. But the 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 in summer, while it is autumn for the western and central Mediterranean region and winter in the eastern Mediterranean.
Outside the United States, Canada ranks second on the list for most tornadoes, averaging 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 “pasillo de los tornados”. 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, about seven to 10 moderate to strong tornado events are reported in New Zealand each year.

Southern hemisphere tornadoes generally rotate clockwise, which is the opposite of how tornadoes mainly rotate in the northern hemisphere.

Tornado frequency featured around the world.

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