🌪️ What Is Extreme Weather?
Most days the weather is fairly calm — a bit of sun, some cloud, maybe a shower. But sometimes nature unleashes its most powerful and dangerous forces. Extreme weather means weather events that are far stronger, faster or more destructive than normal, such as tornadoes, tsunamis, hurricanes, floods and blizzards. Scientists who study these events are called meteorologists (for weather) and seismologists (for earthquakes and tsunamis). By understanding how they work, we can warn people in time and save lives. In this fact book we’ll take a close-up look at two of the most dramatic: the spinning tornado and the giant tsunami.
🌪️ Tornadoes — Nature’s Spinning Giants
A
tornado is a violently spinning column of air that reaches from a thundercloud down to the ground. From far away it looks like a twisting
funnel of cloud, which is why people call it a “twister”. Tornadoes are among the most violent storms on Earth — their winds can spin faster than
480 km/h (300 mph), strong enough to lift cars, tear roofs off houses and even pick up whole buildings. Most tornadoes are actually quite small and weak, but the biggest ones can carve a path of damage over a kilometre wide.
🌀 The United States has more tornadoes than anywhere else on Earth — over 1,000 every year!
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How a Tornado Forms
- Tornadoes form during huge thunderstorms called supercells
- Warm, moist air rises quickly and meets cold, dry air above
- Winds at different heights make the air begin to spin
- When the spinning funnel touches the ground, it becomes a tornado
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The Fujita Scale
- Tornado strength is measured on the Enhanced Fujita (EF) Scale
- It runs from EF0 (weakest) to EF5 (strongest)
- An EF0 snaps branches; an EF5 can rip a house off its foundations
- The scale was created by scientist Dr Tetsuya “Ted” Fujita
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Tornado Alley
- Most tornadoes happen in a part of the USA called Tornado Alley
- It stretches across states like Texas, Oklahoma, Kansas and Nebraska
- Tornado season is usually from March to June
- Tornadoes also happen in Canada, Bangladesh, Argentina and Australia
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Amazing Tornado Facts
- The fastest tornado winds ever measured were over 480 km/h
- A tornado can move across the ground at up to 110 km/h
- The Tri-State Tornado of 1925 travelled over 350 km — the longest ever
- In the Northern Hemisphere, most tornadoes spin anticlockwise
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Staying Safe in a Tornado
- A tornado watch means one could form; a warning means one is happening
- The safest place is a basement or a small inside room with no windows
- Stay away from windows — flying glass and debris are very dangerous
- Scientists use Doppler radar and storm chasers to spot them early
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Different Kinds of Twister
- A waterspout is a tornado that forms over water
- A wedge tornado is so wide it looks like a dark block of cloud
- A rope tornado is thin and twisty, often as it fades away
- Some storms make several small funnels called a multiple-vortex tornado
🌊 Tsunamis — Giant Waves From the Deep
A
tsunami is a series of enormous ocean waves caused by a sudden movement of a huge amount of sea water — most often by a powerful
underwater earthquake. The word “tsunami” is Japanese and means
“harbour wave”. Out in the deep ocean a tsunami is barely noticeable, but it races along as fast as a jet plane — up to
800 km/h (500 mph). As it reaches shallow water near the coast, it slows down and piles up into a towering wall of water that can be over
30 metres tall. Unlike a normal wave, a tsunami keeps coming and coming, pushing far inland.
🌊 A tsunami is not a single wave — it is a whole train of waves, and the first one is often not the biggest!
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How a Tsunami Forms
- Most tsunamis start with a large undersea earthquake
- When the seafloor suddenly jolts, it pushes a huge amount of water upward
- That water spreads out in every direction as a series of fast waves
- They can also be caused by underwater landslides or volcanic eruptions
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How Fast and How Big?
- In deep water a tsunami travels up to 800 km/h — as fast as a jet
- Far out at sea the wave may be less than a metre high and hard to spot
- Near the coast it slows down and grows into a huge wall of water
- The biggest tsunami waves have reached over 30 metres tall
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Nature’s Warning Signs
- A key warning sign is the sea suddenly pulling far back from the shore
- This is called the drawback — it exposes the seabed and fish
- A strong earthquake near the coast can be a warning a tsunami is coming
- Some animals seem to sense danger and move to higher ground early
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Famous Tsunamis
- The 2004 Indian Ocean tsunami was one of the deadliest natural disasters ever
- It was triggered by a massive earthquake near Sumatra
- The 2011 Japan tsunami followed a huge earthquake off the coast
- The 1883 Krakatoa volcano made a tsunami with waves up to 40 metres
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Staying Safe From a Tsunami
- If you feel a strong earthquake near the sea, move to high ground straight away
- Never go down to watch the sea pull back — that is a danger sign
- Wait for the all-clear: more waves can arrive for hours afterwards
- Coastal towns have warning sirens and evacuation routes
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How Scientists Watch the Oceans
- The word tsunami comes from Japanese: “tsu” (harbour) + “nami” (wave)
- Scientists use ocean buoys and pressure sensors on the seafloor
- The Pacific warning system is called DART
- Tsunamis have nothing to do with the tides — the old name “tidal wave” is wrong
🌩️ More Extreme Weather
Tornadoes and tsunamis aren’t the only powerful forces of nature. Here are a few more kinds of extreme weather from around the world.
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Hurricanes
- Giant spinning storms that form over warm tropical oceans
- Called typhoons in Asia and cyclones in the Indian Ocean
- Bring ferocious winds, heavy rain and a dangerous storm surge
- The calm centre is called the eye of the storm
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Blizzards
- Severe snowstorms with strong winds and low visibility
- Can bury cars and houses under deep snow drifts
- Very cold temperatures can be dangerous for people and animals
- The whirling snow can cause a “whiteout” where you can’t see
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Floods & Droughts
- A flood happens when too much water covers land that is normally dry
- A drought is a long period with very little or no rain
- Both can be caused by extreme weather patterns
- Climate change can make floods and droughts happen more often
🤔 Extreme Weather Quiz
Click each answer to check it instantly!
Question 1 of 8
What do we call the spinning funnel of air that reaches from a thundercloud to the ground?
- A hurricane
- A tornado
- A tsunami
- A blizzard
Question 2 of 8
What scale is used to measure how strong a tornado is?
- The Richter Scale
- The Beaufort Scale
- The Enhanced Fujita Scale
- The Celsius Scale
Question 3 of 8
The part of the USA that gets the most tornadoes is nicknamed what?
- Storm Street
- Tornado Alley
- Twister Town
- Wind Valley
Question 4 of 8
What is the most common cause of a tsunami?
- A rainstorm
- A strong wind
- An underwater earthquake
- A high tide
Question 5 of 8
What does the Japanese word ‘tsunami’ mean?
- Big wave
- Harbour wave
- Ocean storm
- Angry sea
Question 6 of 8
What is an important natural warning sign that a tsunami is coming?
- The sea suddenly pulls far back from the shore
- The sky turns green
- It starts to snow
- Birds start singing loudly
Question 7 of 8
Roughly how fast can a tsunami travel across the deep ocean?
- As fast as a person can run
- As fast as a car in town
- As fast as a jet plane (up to 800 km/h)
- Faster than the speed of light
Question 8 of 8
What is the safest thing to do if you are near the coast and feel a strong earthquake?
- Run down to watch the sea
- Move quickly to higher ground
- Stay exactly where you are
- Go for a swim
📚 Key Words
tornado
A violently spinning column of air that reaches from a thundercloud down to the ground.
funnel
The cone or tube shape of a tornado, made visible by cloud, dust and debris.
supercell
A large, powerful and long-lasting thunderstorm that can produce tornadoes.
Fujita scale
The scale (EF0 to EF5) used to rate how strong a tornado is by the damage it causes.
tsunami
A series of huge ocean waves, usually caused by a large underwater earthquake.
drawback
When the sea suddenly pulls back from the shore before a tsunami arrives — a warning sign.
earthquake
A sudden shaking of the ground caused by movement deep inside the Earth’s crust.
meteorologist
A scientist who studies the weather and helps to forecast storms.
evacuate
To move away quickly from a dangerous area to somewhere safe.
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