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The Science of Tornadoes, Funnel Clouds, Twisters, Cyclones

Updated on August 28, 2011

The Science of Tornadoes

The name 'tornado' comes from the Spanish word 'tronada'. The other common names for tornadoes are: twister, funnel, or funnel cloud, and cyclone.

This is about the different types tornadoes and how they occur, plus other helpful information.

Huge Tornado Government Image
Huge Tornado Government Image

About Tornadoes

Tornadoes are characterized by rapidly rotating columns of air hanging from cumulonimbus clouds.

These are a type of cloud that is tall, dense, and involved in thunderstorms and other intense weather. The clouds can form alone, in clusters, or along a cold front in a squall line.


Formed by an instability in the atmosphere.

Usually form during thunderstorms.

A downward flow of cold air from clouds meets a rising flow of warm air from the ground.

When the conditions are just right, a tornado will start.

There is a spiraling effect of the air from a the warm air rising to meet the cold air that is descending.

Courtesy of Sarge Devil on Flickr

The following map (below) shows the frequency in which tornadoes occur in the United States.

Tornado alley is more like a blob. A big, nasty blob. If you live in this area you are likely to see 6 or more tornadoes per year via the news or in person.

Most tornadoes have wind speeds between 40 mph (64 km/h) and 110 mph (177 km/h), are approximately 250 feet (75 m) across, and travel a few miles (several kilometers) before dissipating. Some attain wind speeds of more than 300 mph (480 km/h), stretch more than a mile (1.6 km) across, and stay on the ground for dozens of miles (more than 100 km).

- Referenced from Wikipedia

Multiple Funnel Clouds

Multiple Funnel Clouds
Multiple Funnel Clouds

First Hand Video

Types of Tornadoes

True tornadoes

Multiple vortex tornado

A multiple vortex tornado is a type of tornado in which two or more columns of spinning air rotate around a common center. Multivortex structure can occur in almost any circulation, but is very often observed in intense tornadoes. These vortexes often create small areas of heavier damage along the main tornado path.

Satellite tornado

A satellite tornado is a term for a weaker tornado which forms very near a large, strong tornado contained within the same mesocyclone. The satellite tornado may appear to "orbit" the larger tornado (hence the name), giving the appearance of one, large multi-vortex tornado. However, a satellite tornado is a distinct funnel, and is much smaller than the main funnel.


A waterspout is defined by the National Weather Service simply as a tornado over water. However, researchers typically distinguish "fair weather" waterspouts from tornadic waterspouts.

* Fair weather waterspouts are less severe but far more common, and are similar in dynamics to dust devils and landspouts. They form at the bases of cumulus congestus cloud towers in tropical and semitropical waters. They have relatively weak winds, smooth laminar walls, and typically travel very slowly, if at all. They occur most commonly in the Florida Keys and in the northern Adriatic Sea.

* Tornadic waterspouts are more literally "tornadoes over water". They can form over water like mesocyclonic tornadoes, or be a land tornado which crosses onto water. Since they form from severe thunderstorms and can be far more intense, faster, and longer-lived than fair weather waterspouts, they are considered far more dangerous.


Landspout (officially known as a dust-tube tornado) is a tornado not associated with a mesocyclone. The name stems from their characterization as essentially a "fair weather waterspout on land". Waterspouts and landspouts share many defining characteristics, including relative weakness, short lifespan, and a small, smooth condensation funnel which often does not reach the ground. Landspouts also create a distinctively laminar cloud of dust when they make contact with the ground, due to their differing mechanics from true mesoform tornadoes. Though usually weaker than classic tornadoes, they still produce strong winds and may cause serious damage.

Tornado-like circulations


A gustnado (gust front tornado) is a small, vertical swirl associated with a gust front or downburst. Because they are technically not associated with the cloud base, there is some debate as to whether or not gustnadoes are actually tornadoes. They are formed when fast moving cold, dry outflow air from a thunderstorm is blown through a mass of stationary, warm, moist air near the outflow boundary, resulting in a "rolling" effect (often exemplified through a roll cloud). If low level wind shear is strong enough, the rotation can be turned horizontally (or diagonally) and make contact with the ground. The result is a gustnado. They usually cause small areas of heavier rotational wind damage among areas of straight-line wind damage. It is also worth noting that since they are absent of any Coriolis influence from a mesocyclone, they seem to be alternately cyclonic and anticyclonic without preference.

Dust devil

A dust devil resembles a tornado in that it is a vertical swirling column of air. However, they form under clear skies and are rarely as strong as even the weakest tornadoes. They form when a strong convective updraft is formed near the ground on a hot day. If there is enough low level wind shear, the column of hot, rising air can develop a small cyclonic motion that can be seen near the ground. They are not considered tornadoes because they form during fair weather and are not associated with any actual cloud. However, they can, on occasion, result in major damage, especially in arid areas.

Fire whirl

Tornado-like circulations occasionally occur near large, intense wildfires and are called fire whirls. They are not considered tornadoes except in the rare case where they connect to a pyrocumulus or other cumuliform cloud above. Fire whirls usually are not as strong as tornadoes associated with thunderstorms. However, they can produce significant damage.

Steam devil

A steam devil is a term describing a rotating updraft that involves steam or smoke. A steam devil is very rare, but they mainly form from smoke emitting from a power plant smokestack. Hot springs and deserts may also be suitable locations for a steam devil to form. There have also been reports of cold air steam devils as well.

- From Wikipedia

A 'man-made' Fire Whirl

A 'man-made' Fire Whirl
A 'man-made' Fire Whirl

Fujita Scale of Tornado Ratings

- The effect of an F5 tornado on a truck.

F-Scale Number

Intensity Phrase

Wind Speed

Type of Damage


Gale Tornado

40-72 mph

Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards.



Moderate tornado

73-112 mph

The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.



Significant tornado

113-157 mph

Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.



Severe tornado

158-206 mph

Roof and some walls torn off well constructed houses; trains overturned; most trees in forests uprooted.



Devastating tornado

207-260 mph

Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.



Incredible tornado

261-318 mph

Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-inforced concrete structures badly damaged.



Inconceivable tornado

319-379 mph

These winds are very unlikely. The small area of damage they might produce would probably not be recognizable along with the mess produced by F4 and F5 wind that would surround the F6 winds. Missiles such as cars and refrigerators would do serious secondary damage that could not be directly identified as F6 damage. If this level is ever achieved evidence for it might only be found in some manner of ground swirl pattern for it may never be identifiable through engineering studies


Tornado Safety

Prevention and practice before the storm:

Make sure you have a plan for you and your family

Keep an emergency supply of water, a charged flashlight, a battery powered radio, and any needed medicine or other supplies available in your safety area.

In a house with a basement:

+ Avoid windows

+ Know where heavy objects are in the house (refrigerators, pianos, etc) and directly above you on the above level. The floor may be weakened and the heavy object could fall through and onto you.

+ Find a sturdy table to crawl under or mattress and cover yourself with it.

In a house without a basement:

+ Avoid windows

+ Go to the lowest floor, small center room (like a bathroom or closet), under a stairwell, or in an interior hallway.

For more helpful advice, especially for other scenarios, please go to Government Tornado Safety

The greatest danger?

Flying debris is the greatest danger in tornadoes

Tornado Video

This is what NOT to do

This is what NOT to do
This is what NOT to do

Learn to Make Your Own Tornado

You can visit the Weather Related Science Projects for Kids and learn how to make your own tornado. There are a growing list of step by step instructions on how to make barometers, hydrometers and much more.

You may also enjoy

Weather Experiments for Kids



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    • KReneeC profile image

      KReneeC 5 years ago

      Great and informative lens! Where I live, I experience funnel clouds and sirens, but thank goodness have never had one touch down too close to our house.

    • ofdifferentsorts profile image

      Paul Franciskato 5 years ago from Junction City, Kansas

      I enjoyed the First Hand Video and many of the photos!

    • Tiggered profile image

      Tiggered 6 years ago

      Nice selection of tornadoes :) Blessed

    • Elsie Hagley profile image

      Elsie Hagley 6 years ago from New Zealand

      We have a tornado at the weekend in New Plymouth NZ, mid winter, no lost of line but a lot of damage. Thanks for a great lens with quality photos to explain.

    • profile image

      NYThroughTheLens 6 years ago

      Wonderful, informative lens.

    • profile image

      bujanan 6 years ago

      What a great lens!!! Excellent job on picture and video selection.

    • Blackspaniel1 profile image

      Blackspaniel1 6 years ago

      I have seen one, but had no damage from it.

    • Krafick profile image

      Krafick 6 years ago

      I've lived the passage of devastating cyclones many times but never that of a tornado.

    • profile image

      anonymous 6 years ago

      Another great lens

    • norma-holt profile image

      norma-holt 7 years ago

      What horrifying things these twisters are. In Australia we have cyclones and they are almost as devastating although mainly coastal tropical regions. I am featuring this on Floods, Drought and Climate Change

    • profile image

      ShamanicShift 7 years ago

      I would dream of tornadoes when I was in a turmoil and the trouble or issue would soon resolve, usually during next day.

    • profile image

      ohcaroline 7 years ago

      I lived through a tornado in 2007. It went right over the house and down the street. I hope it was the last one. Scary thing to go through.

    • Mihaela Vrban profile image

      Mihaela Vrban 7 years ago from Croatia

      We don't have tornadoes in Croatia, for now at least. With all these climate changes, it's bound to change in future. I find them fascinating. Probably because I've never seen one in real. Must be scary. Nature in all her power breking down on you.

    • ElizabethJeanAl profile image

      ElizabethJeanAl 7 years ago

      I saw a tornato as a teenager and again during Hurricane Hugo. They are a scary sight.

      Lensrolled to Hurricanes.


    • eclecticeducati1 profile image

      eclecticeducati1 7 years ago

      Cool lens! Lensrolling to my weather lapbook lens.

    • eclecticeducati1 profile image

      eclecticeducati1 7 years ago

      Cool lens! Lensrolling to my weather lapbook lens.

    • NanLT profile image

      Nan 7 years ago from London, UK

      I was surprised to find out that we have small tornadoes here in the UK as well. Thanks for all the information on the different types of tornadoes. I'd never heard of most of them.

      Added to "Another 100 Lenses for my 200th Lens"

    • VarietyWriter2 profile image

      VarietyWriter2 7 years ago

      Another great lens by you :)

    • profile image

      julieannbrady 7 years ago

      OMG, living in Ohio, we surely got to experience lots of tornadoes and tornado warnings. It's only been once in a while that we might here about a tornado here in Jacksonville, but they do occur here. I'm pretty sure I would be braver in a hurricane than in a tornado you know? Tornadoes are pretty scary ... rather Mother Nature and all that hot air.

    • PNWtravels profile image

      Vicki Green 7 years ago from Wandering the Pacific Northwest USA

      I was in Dallas, Texas a few years ago when one touched down at the airport. Since I'm not from an area that has tornadoes, I had no idea why the sky was such a funny color until I heard the news later.

    • LadyFlashman profile image

      LadyFlashman 7 years ago from United Kingdom

      Wonderfully scary photos! I have added your lens to my featured lenses on my cloud lens.

    • Sylvestermouse profile image

      Cynthia Sylvestermouse 7 years ago from United States

      I love to look at pictures of actual tornadoes but I do not like to see or experience the destruction of one. I think I can enjoy the little tornado lab for the rest of my life and stay away for the real thing. Great lens with some really interesting and beautiful pictures!

    • julcal profile image

      julcal 7 years ago

      Great lens topic. I'm back in Chicago and I've seen my share of tornado watches, warnings, funnel clouds and an actual tornado. Most frightening thing ever. I've lived through a hurricane, but you can watch them coming, gauge their severity, decide whether to leave. A tornado pops out of nowhere and devours everything in its path - BAM! 5*

    • paperfacets profile image

      Sherry Venegas 8 years ago from La Verne, CA

      This is a very interesting lens. Enjoyed it.

    • Ramkitten2000 profile image

      Deb Kingsbury 8 years ago from Flagstaff, Arizona

      This was really interesting. I see that Flagstaff, Arizona is in the yellow on the map, but I don't think there's ever been a twister right IN town (that I know of). Tornadoes are awesome things ... to see in photos and on TV ... but I don't know that I'd ever want to live in an area that gets lots of them.

    • julcal profile image

      julcal 8 years ago

      Incredible lens! 5* FAV and Tweet! Super! I live in Chicagoland and the green-skyed, eery feeling, that comes before a tornado-filled storm is well-known to me.

    • KimGiancaterino profile image

      KimGiancaterino 8 years ago

      Congratulations on your purple star. Squid Angel Blessed.

    • profile image

      anonymous 8 years ago

      Excellent Lens. 5*

      If you get a chance check out my Instant Stress Management lens.

    • profile image

      anonymous 8 years ago

      Just returning to say congratulations on your purple star, this is one of the best lenses I have seen in the Animals and Nature category. Blessings!

    • EpicFarms profile image

      EpicFarms 8 years ago

      Wow! Awesome photographs and some excellent information. Congratulations on your purple star :o) Wonderful lens for reference!

    • eagleassets profile image

      eagleassets 8 years ago

      nice lens and congrats on the Purple Star Award!

    • profile image

      Cassandrology 8 years ago

      nice job in this lens, information about twister and tornadoes? I found it all here.

    • Mickie Gee profile image

      Mickie Goad 8 years ago

      Nice work. Love the eerie photos.

      I live in the SE USA and we get lots of severe weather. My husband lovingly makes fun of my paranoia of "severe weather".

      Lensrolled you to my "derecho" lens. It is about another form of weather I can get nervous about!

    • AlisonMeacham profile image

      AlisonMeacham 8 years ago

      Congratulations on your Purple Star!

    • profile image

      anonymous 8 years ago

      Congratulations on your Purple Star Award - Kathy

    • evelynsaenz1 profile image

      Evelyn Saenz 8 years ago from Royalton

      Congratulations on your well deserved Purple Star Award!

    • Paula Atwell profile image

      Paula Atwell 8 years ago from Cleveland, OH

      Blessed by a Squidoo Angel.

    • religions7 profile image

      religions7 8 years ago

      Great lens - you've been blessed by a squidoo angel :)

    • PleasantValley LM profile image

      PleasantValley LM 8 years ago

      I enjoyed reading this lens. It reminded me of the day when I saw two fair weather waterspouts merge into one over the sea. It was a beautiful sight! By the way, where's the link to "The Wizard of Oz"? :)

    • gypsyman27 lm profile image

      gypsyman27 lm 9 years ago

      Uncle Henry, Auntie Em, ToTo, it's a twister! Good lens 'T', five stars and add to my favorites list, see you around the galaxy

    • profile image

      beachbum_gabby 9 years ago

      Wow, what a twister. Awesome lens!

    • profile image

      anonymous 9 years ago

      great lens..and the videos and pictures are awesome..

      good job..

    • mdvaldosta lm profile image

      mdvaldosta lm 9 years ago

      Whoa, some really neat pictures. It's amazing how something can be so beautiful yet so dangerous at the same time.

    • Andy-Po profile image

      Andy 9 years ago from London, England

      Excellent lens. I do enjoy watching extreme weather. We don't get many big tornadoes here in the U.K. though. Good to see an detailed description of how these things occur.

    • grandma deal profile image

      grandma deal 9 years ago

      I live in Oklahoma and tornadoes hit all around us every year. So far we've been blessed in that our home has only received hail damage from them. They really are extremely dangerous and very frightening. This is a 5* tutorial.

    • naturegirl7s profile image

      Yvonne L. B. 9 years ago from Covington, LA

      Fantastic lens. Ooh, my skin is prickly just reading it. The tornadoes that H. Katrina spawned did most of the damage to our area on the North Shore. Won't you please consider joining our group Naturally Native Squids: ?

    • papawu profile image

      papawu 9 years ago

      I am from California and I must admit that I will take an earthquake over a tornado any day! Hurricanes and tornadoes are not something I am overly keen on experiencing. The utter destruction they leave in their wakes are utterly terrifying to me. Also, if the photo of the lady taking a picture with the tornado at her back is real, she may need to lay off the pipe a little!

    • profile image

      babyknittingpatterns 9 years ago

      One of my favorite subjects, Fantastic pictures. Loved it.

    • jimmielanley profile image

      Jimmie Lanley 9 years ago from Memphis, TN, USA

      My daughter and I were just studying about dust devils on the prairie today. Interesting.

    • Paula Atwell profile image

      Paula Atwell 9 years ago from Cleveland, OH

      As scary as they are, they are still fascinating. Wonderful lens.

    • Rich-H profile image

      Rich 9 years ago from Surrey, United Kingdom

      Fabulous lens and wonderful read. 5*s.

    • profile image

      anonymous 9 years ago

      Tri - you have just blown me away! Sorry, could not resist. I cannot possibly imagine what it must be like to experience a tornado. I have a dear friend who lives in Alabama. She has learned to listen to the radio. Great lens.

    • ArtByLinda profile image

      Linda Hoxie 9 years ago from Idaho

      Wow, they are so powerful, somehow intrigueing and yet so frightening. I would be excited to see one, and then instantly afraid. Use to have nightmares as a child after watching the wizard of Another extremely well done lens triathlon! Linda

    • YourCover Mama profile image

      YourCover Mama 9 years ago

      AWESOME LENS!!!! I am terrified of tornadoes :o( I don't know why seeing as I have never experienced one...but probably the fear of being in one. Thank you for all your great information!! 5*

    • debnet profile image

      Debbie 9 years ago from England

      Are you a teacher? If not, why not? I learn so much from your lenses...much more than I did in school!! Another very worthy 5* for you!

    • ZenandChic profile image

      Patricia 9 years ago

      Great lens! Tornadoes are fascinating

    • Salvatore LM profile image

      Salvatore LM 9 years ago

      Wow! What a very well built and informative lens! It is the first time I hear about "fire whirls". Excellent job! 5 stars

    • WhiteOak50 profile image

      WhiteOak50 9 years ago

      This lens is really well done. Very good!!

    • Sensitive Fern profile image

      Sensitive Fern 9 years ago

      Another awesome weather lens from you! 5*

    • profile image

      anonymous 9 years ago

      Great lens very important information here you did a great job and excellent research 5 big stars

    • dc64 lm profile image

      dc64 lm 9 years ago

      Love this lens. I know the kind of work that goes into these kinds of lenses, so I really appreciate them. Yours is visually stimulating too, I had to pause a bit longer at some of the pics than I usually do, they were just that interesting.

    • OhMe profile image

      Nancy Tate Hellams 9 years ago from Pendleton, SC

      My brother got a good picture of a funnel cloud one time. This is very interesting and informative. 5*

    • LaraineRoses profile image

      Laraine Sims 9 years ago from Lake Country, B.C.

      Pictures are terrific! Some of the vids don't work though. Interesting subject! I've lensrolled you to remind myself to come back - I'd love to see the one on the Tornado chasers.

      5 stars.

    • profile image

      nelsy70 9 years ago

      My 8 year old son and I really enjoyed this very interesting and imformative lens. This lens was a great, short, summer lesson in a topic he is very interested in. Thanks for all your hard work.

    • profile image

      anonymous 9 years ago

      Wow what a photo! thx for the squid cast

    • profile image

      tdove 9 years ago

      Great lens. 5*. Tornadoes are amazing and I loved the videos here. Thanks for checking out my lens Foot Tattoos.

    • ArtSiren LM profile image

      ArtSiren LM 9 years ago

      Wow, lots of great info on this lens! I particularly liked the 'What NOT to do' photo! lol. Actually I like all the photos - amazing what Nature can create! 5* fave.

    • ElizabethJeanAl profile image

      ElizabethJeanAl 9 years ago

      I saw a tornato back when I was in college and experienced the damage one can cause a few years ago. The tornato took our porch off and some other damage but it destroyed my neighbor's house.

      Great lens,

      5* and lensroll


    • profile image

      cowgirlup1123 9 years ago

      I have always been fascinated with Tornatos

      great lenses

    • profile image

      InspiredWritingResearch 9 years ago

      Educational lens - and fun too, which isn't easy work! This is the kind of lens I would select for research and schoolwork as it's clear and smart! Faved.

    • triathlontraini1 profile image

      triathlontraini1 9 years ago

      Thanks Linda! Yes, you're right, this was quite a bit of work. Very fun though! :)

    • profile image

      anonymous 9 years ago

      Awesome lens! The pictures are great to show what these things can do.

    • ArtByLinda profile image

      Linda Hoxie 9 years ago from Idaho

      This is a very cool lens, I can see you put a lot of work into it! Another well done one for you! :-) Keep up the great work, I'm shining up your stars*****!