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Tornado's - What are tornadoes - how do tornadoes form - Interesting facts about tornadoes

Updated on July 9, 2011

Tornado’s ~ What are they. How do they form. Interesting facts

Why did I write about Tornado’s?

I’m a New Zealander and am living in Auckland at this time. South Auckland had a funnel cloud that came about halfway to the ground but didn’t reach the ground. That evening on the news a New Zealand specialist stated that funnel clouds do not create tornadoes. The next evening on the news there was a story about a tornado in the U.S.A and the specialist from America stated that any funnel cloud that reaches the ground creates a tornado.

Due to the huge numbers of tornadoes that hit parts of the United States I did figure that the information given by their scientists would be the most reliable of sources which made me also wonder if the news got someone to speak who doesn’t know about tornadoes or if the scientific community prefers to keep New Zealanders in the dark in regards to natural disasters. As you can imagine I decided that I needed to find out more about tornadoes and how they are formed etc.

Just this week an F 3 tornado touched down in the North Shore in Auckland killing 1 person and injuring about 20 others at the mall. My partner’s second daughter and granddaughter were both at the mall at the time the tornado hit. Her daughter was working and our one year old granddaughter was in kindergarten. Both were thankfully safe and unharmed.

Where does the word Tornado come from?

The word Tornado comes from the Spanish word Tronada. The word Tronada actually means thunderstorm.

How do Tornadoes form?

First Theory

Basically tornadoes are created when damp warm air moving in one direction is joined with cold air travelling in the opposite direction.

If the two air systems hit each other with enough pressure they can start to form a circling effect. Both air systems need to be both strong and as strong as each other for this to occur.

This is also the kind of thing that creates thunder and lightning storms which is basically when the two systems rub against each other creating friction which can be released as a lightning strike and / or a clap of thunder. Most often tornadoes form during a lightning storm.


Back to the tornado formation and what happens if the two pressure systems start spinning. This circling effect can build up creating a funnel like effect. Once this process begins and gets up enough momentum it can form a spout in a matter of 20 or so seconds to a couple of minutes.

If this funnel cloud reaches the ground a tornado has been created. Depending upon its level anything in its path will be sucked up into the spout before getting thrown out to fall back to the ground. Tornadoes can send corrugated iron or other things shooting out of it at around 300 miles per hour.

Second and Third Theories

This theory differs in a few integral ways from the first theory. Basically you have cold dry air travelling in one direction and warm moist air gets trapped underneath it. There seems to be some dissention regarding whether the warm air is moving in the opposite direction to the cold air or not.

Again there are two differing views to the next part. Either the warm air rises because it is pushed upwards because the hot air near the ground rises or because an influx of cold air lower down pushes it upwards.

Though I can understand how the twisting motion can occur when the two systems are travelling in differing directions I have yet to find any logical explanation for how this circling effect would occur if the hot air was stagnant.

If the now created funnel cloud reaches the ground it has created a tornado.

Tornado formation video

What are the different levels of a tornado?

Tornadoes are ranked on a scale from F0 to F5. It’s like a Richter scale for tornadoes. So the different levels let us know what to prepare for in regards to the destructive forces of an incoming tornado.

The scale is called the Fujita scale and is named after the scientist who developed it.

F0 ~ winds of less than 73 miles per hour (116 kph); F0 tornadoes are called "gale tornadoes"

Break tree branches

Damage signs

Take off roof shingles

F1 ~ winds from 73 to 112 mph (117-180 kph); F1 tornadoes are called "moderate tornadoes."

Peel surfaces off of roofs

Push cars off of the road

Push mobile homes off of their foundations or even overturn them

F2 ~ winds from 113-157 mph (181-253 kph); F2 tornadoes are called "significant tornadoes"

Demolish mobile homes

Overturn railroad boxcars

Uproot or snap large trees

Tear the roofs off of light frame houses

F3 ~ winds from 158-206 mph (254-332 kph); F3 tornadoes are called "severe tornadoes."

Tear roofs off of well-constructed houses

Uproot the trees in a forest

Lift cars off the ground.

Overturn entire trains

F4 ~ winds from 207-260 mph (333-416 kph), F4 tornadoes are called "devastating tornadoes."

Level well-constructed houses

Move structures with weak foundations some distances

F5 ~ winds from 261-318 mph (417-509 kph); F5 tornadoes are called "incredible tornadoes."

Move well-constructed homes a distance

Cause incredible damage and phenomena to occur

Lift trains boats and planes off the ground

F6 ~ winds above 318 mph (509 kph); F6 tornadoes are considered "inconceivable tornadoes."

No F6 tornadoes have ever been recorded

When do tornadoes occur?

It’s important to know first off that tornadoes can and do occur at any time of the year.

However the most prevalent times of the year for tornadoes is normally from early springtime to mid-summer.

The most common time of day for tornadoes to occur is during the afternoon.

Interestingly enough the Month of the year in which the most tornadoes occur is May. This is closely followed unsurprisingly by June having the second highest amount of tornadoes per year. Please note that this is based upon the stats for tornadoes that have been recorded since 1950 however these months may not always be the same.

As far as I have been able to find out the month that had the highest occurrences of tornadoes was May 2003 which had 543 confirmed tornadoes.

I haven’t found out as yet which year had the most tornadoes but as soon as I can find the information I will let you all know.

Myth busting

Do not take shelter under a bridge unless you have no choice. This is in fact a very dangerous place to be. I must admit that I was one of the people who believed this to be a safe place but have whilst do this research found time after time statements warning against this.

Do not open the windows of your house to equalise the air pressure. Opening the wrong windows can in fact allow the air to rush into your home and destroy it by literally blowing it apart from the inside. Again this was information that before doing my research I believed to be true and I would have definitely opened windows on the opposite side to the direction the tornado was coming at my house.

Fun Facts about Tornadoes

A tornado was photographed by a hiker at 12,000 feet on July 7th 2004. This is thought to be the highest altitude any tornado has been photographed at. The photo was taken in the Sequoia National Park in California.

Waterspouts are in fact tornadoes that have formed over a small body of water like a lake or river.

Dust Devils are tornadoes that pass over deserts. Interestingly ancient people believed that dust devils were in fact ghosts.

A weak tornado is sometimes called a whirlwind and some people believe these are how crop circles are created in the UK. There is no evidence to prove this either way that I have found.

Any thunderstorm which is thought to be extremely likely to create a tornado is actually called a supercell.

All tornadoes start out white or grey in colour and quickly change colour to match the ground their travelling across. The more items tornadoes pick up the darker in colour they become. Some tornadoes look like a black swarm moving across the land.

If a Tornado travels across empty fields and hasn’t picked up anything significant it sounds almost like a strong wind in the trees. The more items a tornado picks up the louder it gets.

Sometimes smaller tornadoes will form near or on the edges of larger tornadoes. A group of tornadoes travelling together is called a swarm.

The safest place to be during a tornado is underground in a basement or storm cellar.

Knives and forks are sometimes found embedded in tree trunks after a tornado. This is probably due to the fact that tornadoes can send items shooting out of them at over 300 miles an hour.

Although I am unsure what direction tornadoes travel in most countries, In the USA tornado chasers stop to the southeast which is normally but not always the safest place of the tornado their chasing. Tornadoes in the USA normally but not always travel from the place they are created from southwest to northwest though not in a perfectly straight line.

Please note - Tornadoes can change direction in a heartbeat and travel in any direction.

Interestingly 3 out of every 4 tornadoes that occur in the world happen in the USA. There seems to be slight dissention as to whether the USA has approximately 800 or 1000 tornadoes a year. Either way that’s a huge amount for 1 country.

The UK has approximately 60 tornadoes a year.

Amazing survivors

In Oklahoma it was reported that a small herd of cattle were sucked up by a tornado and carried across the countryside then set down in another field unharmed.

1928 - A tornado in Kansas plucked the feathers off a group of chickens but otherwise left the chickens unharmed in what was left of their coop.

1981 - In the Italian city of Ancona a tornado lifted a sleeping baby from its carriage then set it down nearby safely upon the ground.

There have been some reported cases of people seeing inside a tornado and living to tell about it.

More devastating facts

A tornado can jump as it travels leaving 1 or a few houses alone whilst destroying all others around them.

Rescue workers and scientists often compare the devastation left after a tornado to bomb blasts.

F4 and F5 tornadoes account for approximately 70 per-cent of deaths due to tornadoes even though they only account for around 1 per-cent of all the tornadoes in the world.

Dozens of people die every year due to tornados.

Tornadoes can either level a house or lift it up and drop it down the street.

Tornadoes have been known to send a car shooting out of it to land more than 100 metres away.

1925 – On March 18th the deadliest single tornado cut a devastating path across Missouri, Illinois and Indiana. It travelled a staggering 219 miles and killed 695 people and injured approximately another 2,000 people. It was called the Tri-State Tornado.

1931 – In Mississippi a tornado sucked up an 83 ton train then threw it 80 feet from its tracks.

Tornado chasers have a high incident of car crashes which are normally due to getting hit by vehicles fleeing the tornado they are chasing.

Tornado Chasers

It is amazing what tornado chasers do for a living. Because of them scientists have and are still learning heaps about tornadoes. Tornado chasers at times place themselves into the direct path of the tornadoes they are chasing. They do this to place instruments in the tornadoes path hoping that the tornado will suck the item up into it and allow scientists to read the information sent back. This allows the scientists to learn more about tornadoes. It also places the chasers in a very real life and death race to get out of the path of the tornado so they too are not sucked into the swirling vortex.

Many countries have tornado chasers however the USA understandably has a lot more than any other country. The area of land known as Tornado alley stretches from West Texas to North Dakota. This is because the moist hot (tropical) air from the Gulf of Mexico hits the dry cold (polar) air from Canada.

Tornado chasers use the weather channels and meteorologists maps to track the most likely area for a tornado to be created. Once they have found a tornado they can drive hundreds of miles during a single tornado chase. Tornado chasers have to be aware not only of the tornado they are chasing but the very real possibility of smaller tornadoes that can be born at the edges of the original tornado. They also have to be very aware of lightning and hail that is a normal part of the extreme weather patterns that accompanies tornado formation.

I wish to say Thank you to all the men and women who chase these tornadoes and place themselves into harm’s way so that scientists may learn about tornadoes. Let’s not forget all the chasers that have lost their lives during the chase, to them I also say Thank you. Because of the job these people have done and still do scientists have been able to create and put in place tornado watches and tornado warnings.

Please DON’T - chase tornadoes unless you know what you’re doing or are with people who know what they are doing.

Click here to read an article about a real storm chaser

How do you prepare for a tornado?

Many homes in tornado alley have basements or storm cellars. If your home has one of these you should stock it with enough canned food and water to last you a week. Also bedding, warm clothes and a medical kit would be great items to have. I also suggest having a radio and a cell phone. Also put a shovel a bucket and an axe in your basement/storm cellar. The axe and shovel would be good if you have to dig your way out and the bucket may be needed to either help with that or to be used as a place to go toilet if your cellar doesn’t have any conveniences.

Most countries have a weather channel on both the radio and the T.V. Also tornado watches and warnings are placed across the bottom of local T.V’s.

A tornado watch – This means the weather in the area is likely to create a tornado in the next few hours. Even if a tornado doesn’t form there will be severe storm weather conditions in the next few hours.

A tornado warning – This means a tornado has been spotted in the area or that the storm is spiralling which can quickly produce tornadoes. You should seek shelter immediately.

If you do not have a basement or storm cellar go to an interior room (one that has no windows) or get into a closet.

Tornadoes versus Hurricanes

Hurricanes are created the same way as Tornadoes however they are created out to sea. Because they are created over the ocean there spouts tend to grow a lot bigger and for some reason they don’t normally spin quite as fast as a tornado does. I am unsure if this is to do with the staggering amount of water they suck into their spout or if this is due to some other reason.

Hurricanes damage is mainly due to flooding and the storm surge as it hits the coast line. Hurricanes tend to dissolve once they have dumped all the water there carrying onto the land they hit. I believe this has something to do with how wide the spout becomes due to the large amounts of water they draw from the sea. It appears the spout is too wide to hold itself together on land and it collapses.

Hurricanes do tremendous amounts of damage over a wider area than its cousin the tornado. In saying that tornadoes can and do cause horrific wind damage and can travel hundreds of miles doing so.

In reality either one of these storms are devastating if they occur in or hit any built up areas.


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    • Lyn.Stewart profile image

      Lyn.Stewart 5 years ago from Auckland, New Zealand

      Thanks for stopping by and your kind remarks sgbrown ... I will have to go check out your tornado hub. I hope you have a fab day as well.

    • sgbrown profile image

      Sheila Brown 5 years ago from Southern Oklahoma

      Hi Lyn! You have done an excellent job with this hub. I recently wrote on tornadoes too, but I have to say, you have done a much better job! Voted this up and useful! Have a great day! :)

    • Lyn.Stewart profile image

      Lyn.Stewart 5 years ago from Auckland, New Zealand

      Thank you freelanceauthor

    • freelanceauthor profile image

      freelanceauthor 5 years ago

      Interesting hub. Well-explained and detailed. Voted up

    • Lyn.Stewart profile image

      Lyn.Stewart 6 years ago from Auckland, New Zealand

      Thanks for your kind remarks JC447 ... I wanted to write so that all ages could hopefully learn something. I know that I certainly learnt a lot while doing the research.

    • JC447 profile image

      JC447 6 years ago from Denver, CO

      My son and I are fascinated by anything weather related. Great article and very informative!

    • Lyn.Stewart profile image

      Lyn.Stewart 6 years ago from Auckland, New Zealand

      Thanks for your kind words Movie Maker ... I'm glad you don't get tornado's in the U.K. It is always good to know what to do just in case though.

    • Movie Master profile image

      Movie Master 6 years ago from United Kingdom

      What a fascinating read! Thank goodness we don't get tornado's in the UK.

      Excellent work, thank you for sharing.

    • Lyn.Stewart profile image

      Lyn.Stewart 6 years ago from Auckland, New Zealand

      thanks RichardCMckeown I had fun writing it as well.

    • RichardCMckeown profile image

      RichardCMckeown 6 years ago

      Great review. I really had fun reading this article.

    • Lyn.Stewart profile image

      Lyn.Stewart 6 years ago from Auckland, New Zealand

      Thank you for your kind words prasetio ... I know that I certainly learnt a lot writing it and am pleased that others are also learning from my efforts.

    • prasetio30 profile image

      prasetio30 6 years ago from malang-indonesia

      Hi, Lyn. This was a complete tornado review. I had never read kind of tornado article like this one. Thank you very much for share with us. I learn much from you. Well done, my friend. Vote it up!


    • Lyn.Stewart profile image

      Lyn.Stewart 6 years ago from Auckland, New Zealand

      Thank you Phil we dont get many here either thankfully

    • Lyn.Stewart profile image

      Lyn.Stewart 6 years ago from Auckland, New Zealand

      thanks rorshak they are pretty scary and we only get babies here in New Zealand

    • Phil Plasma profile image

      Phil Plasma 6 years ago from Montreal, Quebec

      Wow, you did an amazing amount of research and have covered this topic amazingly well. Vote up and awesome from me!

      Where I live we don't get very many, though they have been known to happen.

    • profile image

      rorshak sobchak 6 years ago

      Tornadoes are so scary! I hope I never have to experience one. Great write up!

    • Lyn.Stewart profile image

      Lyn.Stewart 6 years ago from Auckland, New Zealand

      thank you alocsin and lets hope that doesn't change for you

    • alocsin profile image

      alocsin 6 years ago from Orange County, CA

      I'm grateful we don't get tornadoes in Southern California. Voting this Up and Useful.

    • Lyn.Stewart profile image

      Lyn.Stewart 6 years ago from Auckland, New Zealand

      Thanks WillStarr

    • WillStarr profile image

      WillStarr 6 years ago from Phoenix, Arizona

      Great work!

    • Lyn.Stewart profile image

      Lyn.Stewart 6 years ago from Auckland, New Zealand

      Thank you misty

    • misty95 profile image

      misty95 6 years ago from uk

      Good work.