Tornadoes

Tornadoes

Middle School

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Learning Objectives

• Describe what a tornado is and how it forms from severe thunderstorms.

• Explain how tornadoes are classified using the Fujita (F) and Enhanced Fujita (EF) scales.

• Identify the area known as 'Tornado Alley' and why tornadoes often form there.

• Describe the damage tornadoes can cause and list important safety tips to follow.

Key Vocabulary

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Tornado

A violently spinning, funnel-shaped column of air that stretches from a thundercloud to the ground.

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Supercell

A strong, rotating thunderstorm with a well-defined updraft that is capable of producing tornadoes.

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Fujita Scale

A scale that measures tornado intensity based on wind speed and the damage it causes.

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Tornado Alley

A region in the central United States where tornadoes are common due to weather patterns.

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What is a Tornado?

• A tornado is a spinning, funnel-shaped column of violently moving air.

• ​It forms in severe thunderstorms, stretching from the clouds to the ground.

• Tornadoes move along the ground, creating a long path of destruction.

• Their powerful winds can reach speeds of more than 250 mph.

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Multiple Choice

Based on the description, which of the following is a key characteristic of a tornado?

• It is a violently spinning, funnel-shaped column of air with high winds.

• It is a wide, slow-moving cloud that causes gentle rain.

• It is a stationary cloud formation that produces loud thunder.

• It always remains high in the atmosphere and never touches the ground.

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How Do Tornadoes Form?

• Tornadoes begin to form inside large thunderstorms called supercells.

• A change in wind creates a rotating column of air called an updraft.

• This spinning updraft forms a funnel cloud that reaches toward the ground.

• When the funnel cloud makes contact with the ground, it becomes a tornado.

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Multiple Choice

What is the final step that must happen for a rotating funnel cloud to be officially called a tornado?

• It must develop within a supercell.

• It must produce heavy rain.

• It must form along a cold front.

• It must touch the ground.

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The Fujita Scale: Measuring Tornado Strength

• Tornado strength is measured by damage using the Fujita Scale, or F-Scale.

• The scale ranges from a weak F0 tornado to a powerful F5 tornado.

• An F0 causes light damage, while an F2 can tear roofs off houses.

• An F4 levels houses, and an F5 has winds from 261-318 mph.

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Multiple Choice

According to the Fujita Scale, what kind of damage would you expect from an F4 tornado?

• Light damage, like broken tree branches.

• Considerable damage, like roofs being torn off houses.

• Moderate damage, such as mobile homes being pushed aside.

• Devastating damage, with houses leveled and cars thrown.

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The Enhanced Fujita (EF) Scale

• Since 2007, the Enhanced Fujita Scale helps to classify tornadoes more accurately.

• It provides an updated list of damage indicators and new wind speed ranges.

• An EF-0 causes minor damage, while an EF-2 can destroy mobile homes.

• An EF-4 causes extreme damage, and an EF-5 causes massive damage.

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Multiple Choice

What is the primary difference between the Fujita Scale and the Enhanced Fujita Scale?

• The EF-Scale measures tornado width instead of wind speed.

• The EF-Scale uses a more detailed list of damage indicators for classification.

• The EF-Scale only has three categories (EF-1, EF-3, EF-5).

• The EF-Scale does not measure damage, only wind speed.

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'Tornado Alley' and Damage

• Tornadoes are common in 'Tornado Alley,' where warm and cold air masses meet.

• Cold, dry air is pushed over warm, humid air, creating a rotating updraft that can lead to tornado formation.

• ​This region includes states like Oklahoma, Kansas, Nebraska, and Texas.

• While a tornado strikes a small area, flying debris can destroy everything.

• The most violent 2% of tornadoes cause 70% of all deaths in the U.S.

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Multiple Choice

Why is the central United States known as 'Tornado Alley'?

• The ground in this area is shaped like a funnel, which encourages tornado formation.

• It has the most tornado shelters in the world.

• Warm, humid air from the south often collides with cold, dry air from the north there.

• It is the only place in the world where tornadoes can form.

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Common Misconceptions About Tornadoes

Misconception	Correction
You can outrun a tornado in a car.	Tornadoes are unpredictable. Abandon your car and seek shelter or lie in a ditch.
The safest place during a tornado is near a window.	Windows are dangerous. Go to an interior room on the lowest floor.
All thunderstorms create tornadoes.	Only powerful, rotating thunderstorms, called supercells, can produce tornadoes.

Multiple Choice

How does the interaction between different air masses contribute to the formation of tornadoes in Tornado Alley?

• Two cold air masses collide, causing heavy snowfall.

• Cold, dry air is pushed over warm, humid air, causing a rotating updraft.

• Two warm air masses merge, creating stability.

• Warm, humid air rises slowly over cool ocean water.

Multiple Choice

A tornado completely destroys several mobile homes, uproots large trees, and tosses cars. What would be its most likely rating on the Enhanced Fujita (EF) Scale?

• EF-0

• EF-1

• EF-2

• EF-4

Multiple Choice

A community is building a new school in Tornado Alley. Based on your knowledge of tornado damage, what structural feature would be most critical to include to protect students?

• An underground basement or reinforced interior storm shelter.

• Large windows for better visibility.

• Locating the school on the highest point in the town.

• A tall, pointed roof to divert wind.

Multiple Choice

If a massive F5 tornado strikes a large city, what would be the most severe and dangerous outcome?

• Minor damage to roofs and gutters, with no serious injuries expected.

• Moderate flooding and power outages lasting a few hours.

• Trees losing their leaves and minor damage to street signs.

• Well-built houses being leveled, cars becoming missiles from high winds, and widespread casualties from flying debris.

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Summary

• Tornadoes are violent, rotating air funnels that form from severe thunderstorms called supercells.

• The Fujita (F) scale rates tornadoes, and many occur in "Tornado Alley".

• The main danger from tornadoes is high-speed flying debris.

• Seek shelter in a basement or an interior room away from windows.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

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• 4