Tornadoes — sometimes called twisters — are rotating columns of air that connect a cumulonimbus cloud with the surface of the Earth. One of the most violent of all weather phenomena, tornadoes are very dangerous and can cause massive damage.

Tornadoes come in all sorts of sizes and shapes. Most often, they take the form of a funnel-shaped cloud with a narrow end touching the Earth. They are usually surrounded by large clouds of debris and dust.

Most tornadoes feature wind speeds under 110 miles per hour, span about 250 feet in width and only travel a few miles before dissipating. The largest, most destructive tornadoes, though, can boast wind speeds of more than 300 miles per hour, span more than two miles in width and remain on the ground for dozens of miles.

Weather experts use the Fujita scale to rate tornadoes based on the damage they cause. Tornadoes can receive a Fujita scale rating from F0 to F5.

For example, an F0 tornado — the weakest possible — can damage trees but not sturdy structures. On the opposite end of the scale, an F5 tornado — the strongest possible — can tear buildings off their foundations and even deform huge skyscrapers.

Tornado Alley” is a term that the media and weather experts use to refer to the area of the United States where the strongest tornadoes occur most frequently. There is no official definition of Tornado Alley, but the area between the Rocky Mountains and the Appalachian Mountains is commonly considered to define the area.

The term was first used by Jennifer Wiley in 1904. The heart of Tornado Alley consists of the Texas Panhandle, Oklahoma, Kansas, Nebraska, eastern South Dakota and the Colorado Eastern Plains. Although no state avoids tornadoes entirely, the strongest ones tend to happen in these areas.

Texas reports the most tornadoes annually, but Kansas and Oklahoma report more tornadoes per land area than even Texas. Florida also experiences a high number of tornadoes each year, although they tend to be weaker storms than those in Tornado Alley.

Weather experts believe that strong tornadoes occur so frequently in Tornado Alley because cold, dry air from Canada and the Rocky Mountains meets warm, moist air from the Gulf of Mexico and hot, dry air from the Sonoran Desert, which is located in the southwestern part of the United States. When these air masses combine with atmospheric instability, they produce intense thunderstorms that spawn destructive tornadoes.


28 Join the Discussion

1 Star2 Stars3 Stars4 Stars5 Stars  (37 votes, avg. 4.19 out of 5)
    • There is definitely no age limit on learning in Wonderopolis, Dave! Thanks so much for stopping by and commenting today! :-)

  1. WOW!!!:O

    That video was sooo incredible. Storm chasers put their lives in danger to learn more about the cow-moving storms which requires lots of bravery. I could not stop watching the video. I was literally biting off my fingernails when the tornado was baring down on the car. I was sure that they would be carried away by the fierce and distuctive cyclone, but it was just their luck that the cyclone started to calm, without even blowing the car a millimeter off the ground.

    I can’t wait for tomorrows’s wonder!!! :) I think that it has something to do with how T.V. shows are made. I have always wondered how in the world they are made ever since I started watching them. I’ve even taken an interest in making my own little short movies with a green screen. I’m excited to learn more about tomorrow’s wonder!

    • What an GREAT comment, Meredith/MC! Tornados can be scary, but people who study them (like some storm chasers and scientists) help us better understand and prepare for them!

      We think it’s so COOL that you like making your own movies! You will REALLY want to check out tomorrow’s Wonder—you will love it! :-)

    • You bet there is, nat19! You can visit Wonderopolis every day for a new, exciting Wonder! Thanks for visiting and commenting today! :-)

  2. Hey Wonderopolis!
    In third grade, I did a report about tornadoes and tornado valley. You sure brought back memories! :)
    P.S. Great Job!

    • Thanks for commenting today, Donielle! :-)

      Tornadoes are very powerful and dangerous! Tim and the other storm-chasing scientists in the video were very lucky that the tornado they were trying to study changed direction in the last seconds. Hopefully the special sensors they put down on the ground will help them study the effects of such powerful storms!

    • We’re so glad, Missy! Thanks for asking about tornadoes so we could share this Wonder with you! You’re a GREAT Wonder Friend! :-)

    • Wow, Natalia! That sounds scary! We’re sure glad you and your friends are OK now. Thank you for sharing your tornado story with us today!

  3. WOW, what a great website. The students in my reading group are reading a book called Storm Chasers, by Alice Cary. One student had no background knowledge, so this wonder was awesome. Keep up the WONDERful job!!

    • Your comment was extra WONDERful, Elizabeth…it made our day! We’re glad you and your classmate found this Wonder to give you both some background knowledge for your reading group! That ROCKS! :-)

  4. It is located out back a few minutes in between the two buildings.

    What? You said alley and that’s an alley.

    ha ha ha. I know what your talking about.

    • He he, we think it’s funny that you took our comment so literally, Tyler J! We’re glad to know where the alley is located! Thanks for WONDERing with us! :)

    • That’s great news, Carlos! Being prepared is very important, we’re so happy you and your family will be safe and sound! :)

    • We’re really glad you shared your comment with us, Alex! We agree, bullying is rude and mean. It’s important to remember to treat everyone with respect and kindness – just how you would like to be treated! :)

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>


  • Wonderopolis on Facebook
  • Wonderopolis on Pinterest
  • Print

Have you ever wondered…

  • Where is Tornado Alley?
  • What is a tornado?
  • How is the strength of tornadoes rated?

Wonder Gallery

Try It Out

Real tornadoes are incredibly dangerous. You can learn more about their swirling forces, though, using water, a couple of two-liter bottles and a few simple supplies.

Follow these directions to make your own twister in a bottle!


Still Wondering

Visit National Geographic Xpeditions’ Twister! What To Do in a Tornado lesson to learn more about the basics of tornado safety. Learn about the signs of an approaching tornado and what to do to protect yourself, your family and your pets if you ever experience a tornado firsthand.


Wonder Categories/Tags

Wonder What’s Next?

Lights… camera… action! Join us tomorrow in Wonderopolis as we take a look at the story behind the stories you see on television.

Upload a Photo or Paste the URL of a YouTube or SchoolTube Video.