Tornado Strength

Contributor: Lindsey Congalosi. Lesson ID: 13299

After a tornado in Oklahoma in 1995, researchers collected some of the debris. Most objects landed 15 to 20 miles from the tornado, but some were found more than 150 miles away! How is this possible?

categories

Earth Science, Practical Life Skills

subject
Science
learning style
Auditory, Visual
personality style
Lion, Otter
Grade Level
Middle School (6-8), High School (9-12)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

Audio:

In the 1996 movie Twister, Jo and Bill watch as a tornado tosses a tanker truck like a toy. Watch Twister (1996) - Tanker Scene from Twister Productions:

Clearly, this is a tornado Hollywood-style.

  • But, could it happen?
  • Could a tornado pick up a truck?
  • What about a house? Or a cow?
  • What else could it do?!

Read more to find out!

Can a tornado really toss a truck or flip over a house?

Yes, and more! A thunderstorm has strong winds called updrafts.

An updraft is a powerful wind gust that comes straight up from the ground, sometimes carrying objects (or people!) with it. In a tornado, updrafts can sometimes exceed 150 mph.

If an item is lofted up into the main storm, it can be carried an extremely far distance. This happened during a 1915 tornado in Great Bend, Kansas. Debris rained down over 80 miles from the town, including a sack of flour that traveled over 110 miles and a canceled check from the Great Bend bank that was found 305 miles away in Nebraska.

The picture below shows a waterspout, which is a weak tornado that forms over water.

waterspout

Waterspouts have even been known to pick up and transfer fish and other water creatures such as frogs, jellyfish, worms, or even alligators. But not sharks. Sorry, Sharknado fans.

Even people have been thrown by tornadoes!

In 2006, Matt Suter became the person to be thrown the furthest by a tornado, traveling 1,307 feet. Read Tornado Throws Man Four Football Fields, by ABC News, to learn about his amazing flight.

How do we measure tornado strength?

Tornadoes produce a lot of debris, as you can see in this scene from Twister below.

Twister (4/5) Movie CLIP - Debris on the Road (1996) HD from Movieclips:

Since it is extremely difficult to measure wind speeds while tornadoes are actually happening, we categorize them based on how much they eat, or destroy.

Tornadoes are given a score from the Fujita scale, created by Ted Fujita in 1971. In 2007, the Fujita scale was enhanced and renamed, appropriately, the Enhanced Fujita scale.

Both scales are fairly similar to each other. The Enhanced Fujita scale (EF Scale) was created based on how much destruction happens when the winds are at a certain speed.

Enhanced Fujita scale

Meteorologists, engineers, and tornado evaluators inspect the area hit by a tornado. They may inspect from the ground, from the air during an aerial survey, or both.

aerial survey of damage

To determine the EF level, all available information is used. Ground-swirl patterns, photos of the tornado or resulting destruction, weather data, radar, and even witness testimonies are used to determine the EF scale.

The greater the destruction, the higher the winds in the tornado were; so a higher EF rating is used. Once the EF scale rating has been determined, then we have a good idea of how fast the winds in the tornado were traveling.

If you'd like to see exactly which factors are considered when determining the strength of a tornado, check out The Enhanced Fujita Scale (EF Scale) from the National Weather Service. If you'd prefer significantly more reading (and who wouldn't?!), you can read the original Recommendation for an Enhanced Fujita Scale (EF-Scale) that was submitted in June 2004.

To better understand, watch What's the DIFFERENCE Between the F and EF Tornado Scales? from WildAC:

How big do tornadoes get?

Usually, the higher the EF rating, the larger the tornado. However, this is not always true.

Smaller tornadoes have caused as much significant damage as an EF4 or EF5, and there are occasionally larger tornadoes that cause relatively minor damage.

Watch How Big do Tornadoes Get? from RealLifeLore: 

How much damage do tornadoes cause?

Pecos Hank walks us through a Tornado Damage Countdown: EF0 to EF5:

As you just learned, maximum tornado wind speed is determined based upon the damage caused by the tornado. Each EF level causes a specific severity level of damage. Let's examine each below.

How strong was the first tornado in Twister?

The opening scene of Twister takes place in 1969, when a family finds themselves in a dangerous thunderstorm.

Twister Intro from Phillip Webber:

  • Did you hear the father say that the tornado coming was considered to be an F5?

Notice anything…off…with this? The Fujita scale wasn't developed until two years later! 

Scientists have gone back over historical documents to rate past tornadoes, but there would not have been a Fujita rating in 1969.

There are roughly 2,000 tornadoes reported every year, most of which take place in the United States and Europe. However, only about 70 F5 tornadoes have been recorded since 1950.

Some experts disagree with this number. It is very difficult to distinguish between an F5 and an F4 tornado because buildings are completely destroyed in each scenario.

Watch the tornado chasers discuss the Fujita scale and what an F5 would be like in this scene from Twister.

The Fujita Scale - Twister from WBMoviesOnline:

One of the largest F5 tornadoes in recent history occurred in Joplin, Missouri, in the late afternoon of May 22, 2011.

Sirens were sounded 20 minutes before the tornado hit, but many people ignored them at first. The tornado killed 158 people and injured over 1,100 others. It was the deadliest tornado since 1947 and insurance payouts totaled over $2.8 billion.

Although the hospital in the last photo was still standing after the 2011 tornado, it had to later be demolished because the tornado winds actually shifted the hospital off of its foundation.

When you are fully versed in Fujita levels, move on to the Got it? section to see if you can figure out what level tornado caused the damage in each picture before taking a quiz to see what tornado level you are!

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