What Are Tornadoes Caused By?

Written by Kirstin Harrington
Updated: January 23, 2023
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A tornado is an air column that extends from the clouds to the Earth’s surface and rotates quickly. This drifting funnel-shaped cloud usually moves forward below a major storm system. Tornadoes are usually visible because they almost always have a precipitation funnel of water droplets, dirt, debris, and trash. The one situation where they’re not visible is when they are rain-wrapped. 

A tornado is the most severe atmospheric storm, and although it goes by many names – including vortex, windstorm, cyclone, twister, and typhoon – it is nevertheless crucial to comprehend them. As the writer of this article, I myself have survived a tornado. I was living in Joplin, Missouri during an EF-5 twister and would love to help our readers learn how they can keep safe during severe weather.

Read on to discover everything you need to know about tornadoes, including basic facts and tracking techniques. 

Categorizing Tornadoes

tornado storm

The worst tornadoes are classified as F5’s which have winds exceeding 200 miles per hour


Based on predicted wind speeds and damage, tornadoes are divided into three general categories. Before 2007, the most popular technique used globally for assessing tornado intensity and wind speed was the F-scale. 

Dr. Theodore Fujita is famous for creating the F-scale. Since 2007, a new Enhanced F-scale has been used to determine the strength of tornadoes and the damage they cause in the United States. The Beaufort wind scale was used to calculate the wind speeds in the original F-scale, which had never been tested in actual tornadoes.

To be classified as an F5 tornado, winds must exceed 200 miles per hour. In the United States, F0 or F1 tornadoes account for 80% of all tornadoes. The damage from an F0 tornado is minimal. Buildings might sustain shattered windows, while trees with weak roots could uproot themselves or sustain broken branches. 

Vehicles may be forced off the road during an F1 tornado. Structures’ roofs could sustain major damage, while mobile homes will sustain severe damage. Higher wind speeds and more storm damage are indicated by higher Fujita scale ratings. Despite being extremely rare, an F5 tornado will almost destroy everything in its path.

EF RatingWind Speed
065 to 85 mph
186 to 110 mph
2111 to 135 mph
3136 to 165 mph
4166 to 200 mph
5Over 200 mph

One unique thing about tornadoes is that the wind speed can change dramatically almost immediately. When one smashes into one building, it could be giving off winds of 100 miles per hour. As the tornado moves to the next block over, the speeds could have easily picked up or slowed down by the time it hits the next target. 

Where Do Tornadoes Happen Most?

Knowing how tornadoes arise makes it simpler to grasp why they strike where they do. While tornadoes may originate anywhere in the world, they are more prone to do so in the United States. 

In actuality, the United States experiences more tornadoes annually than any other nation. The region of the country where tornadoes occur most frequently has the nickname “Tornado Alley.” Additionally, the most common locations for powerful tornadoes occur in this region.

The Great Plains are known as Tornado Alley because they frequently see tornadoes. Between the Rockies and the Appalachian Mountains is this section of the Central United States are also part of Tornado Alley. South Dakota, Minnesota, Nebraska, Iowa, Kansas, Missouri, Oklahoma, Texas, and Colorado are among the states that you can find within Tornado Alley. The states that experience the most tornadoes annually per 10,000 miles are Oklahoma and Texas.

What Causes Tornadoes?


Tornadoes are caused

by instability in the atmosphere

©Minerva Studio/Shutterstock.com

When the lower atmosphere is sufficiently turbulent and unstable, severe thunderstorms can produce tornadoes that originate on land. When there are colder temperatures in the upper atmosphere and extremely humid and warm circumstances in the lower atmosphere, instability is produced. The colder layer makes it difficult for the warm, humid air to rise, which leads to instability. 

When the wind shifts its direction and picks up speed and height, wind shear develops. For example, winds traveling at 20 miles per hour on the ground can increase to 1600 miles per hour at an altitude of 16.

The creation of the cyclone is caused by the interaction between instability and wind shear. Just during cold fronts and low-pressure systems will you find this. The intense thunderstorm’s air currents and convection are caused by the wind shear and instability in the air, which tilts the winds and creates a vertical tornado vortex. 

This is impacted by variations in wind direction and speed in the upper atmosphere, which result in a vertical whirling motion in the lower atmosphere. With a circumference of 2 to 6 miles of whirling air, the low-pressure core spins even faster as the air flowing there converges inward into the thunderstorm.

How Does a Tornado Form?

The development of a wall cloud is one of the most reliable signs that a tornado may be present. This massive, isolated wall cloud can occasionally form behind a cumulonimbus cloud throughout a storm, typically in the dry base area of the thunderstorm. Meteorologists and casual observers may identify these clouds because they seem like a thick, vertical cloud that is “heaped” up during a storm. Cumulonimbus clouds are commonly referred to as thunderheads.

Winds of various intensities and orientations inside a storm force the air to spin, which leads to the production of wall clouds. At some point, the storm’s strong updrafts and downdrafts combine to drive the spinning winds vertical, creating a mesocyclone. Warm, humid air is drawn in by this mesocyclone, creating the wall cloud. A wall cloud rotates frequently, albeit not always.

Wall clouds occasionally have whirling funnel-shaped condensation that falls below the cloud’s base. It’s a funnel cloud here. However, they can persist considerably longer. Many funnel clouds only endure a few seconds before disappearing. A funnel cloud turns into a tornado the instant it makes contact with the earth.

Detecting a Tornado

Great Tornado over the road

Tornados often form as part of the hurricane system and are detected using a range of remote sensing equipment


Meteorologists use weather radars, a different type of remote sensing equipment that can detect microwave energy. This is done to observe storms from the surface down to the base of a cloud. Radio detection and ranging are referred to as radar. By sending out brief microwave bursts, radar was created to detect objects and establish their position or range. 

Meteorologists track the strength and source of “echoes” from items struck by microwaves using computers connected to the radar that fired them. Wind direction and speed may be detected with a Doppler radar whereby rotation frequently denotes the onset of tornadic activity.

Tornado Safety Tips

Prepare an emergency kit and plan in advance, pay attention to the weather during thunderstorms, be aware of the best areas to seek refuge both indoors and outside, and always protect your body, especially your head, from harm. 

Each year, tornadoes continue to have an influence on different parts of the nation, bringing with them powerful winds and destroying everything in their path. Safety throughout a tornado is not promised, according to the National Oceanic and Atmospheric Agency (NOAA). 

Be alert to any changes in the local weather if you want to keep yourself and your loved ones safe during a tornado. Keep an eye on local radio and news stations as well as a NOAA weather radio station if you are aware that thunderstorms are imminent. A tornado warning may not be available when some twisters strike quickly.

If you see large hail, the sky is turning green, there are low-hanging clouds, or you hear what sounds like a freight train in the distance, take cover immediately. Avoid being close to any windows or heavy objects by going to the lowest floor’s basement or a room within with no windows. 

Find a nearby structure, ideally, one with a basement, if you are outdoors or living in a manufactured home. Instead of attempting to flee a tornado or seeking refuge beneath an overpass if you are in a car, locate the closest substantial structure.

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The photo featured at the top of this post is © Minerva Studio/Shutterstock.com

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About the Author

Kirstin is a writer at A-Z Animals primarily covering animals, news topics, fun places, and helpful tips. Kirstin has been writing on a variety of topics for over five years. She has her real estate license, along with an associates degree in another field. A resident of Minnesota, Kirstin treats her two cats (Spook and Finlay) like the children they are. She never misses an opportunity to explore a thrift store with a coffee in hand, especially if it’s a cold autumn day!

FAQs (Frequently Asked Questions) 

Can a tornado pick you up?

You could be lifted off your feet and thrown into the air before you even realize you’re in a tornado thanks to the churning updraft of the tornado, which feels like being in an unrelenting blender.

What happens if two tornadoes collide?

One storm can often only capture another if it is significantly bigger and stronger. If not, the two tornadoes gradually separate from one another and move on. There have also been reports of tornadoes revolving around one another.

Is a hurricane or tornado worse?

Even while stronger tornadoes have winds that much outweigh stronger hurricanes, storms normally inflict significantly more harm on a per-storm, per-season, and per-area basis. Economically speaking, tornadoes often do 10 times more damage annually than hurricanes.

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