Are hurricanes, typhoons and cyclones the same thing?

Yes — they are the same kind of storm with different names depending on where they form. They are called hurricanes in the Atlantic and eastern Pacific, typhoons in the western Pacific, and cyclones in the Indian Ocean and around Australia.

Why does the eye of a hurricane feel calm?

In the very centre, air sinks gently instead of rising, so there is little wind or rain and the sky may even be clear. But it is dangerous to go outside, because the violent eyewall winds return suddenly once the eye passes.

What is Tornado Alley?

Tornado Alley is an informal name for a region of the central United States, including states like Texas, Oklahoma and Kansas, where conditions often combine to produce many strong tornadoes each year.

Hurricanes and Tornadoes | Nature

Two very different storms

Hurricanes and tornadoes are both spinning storms, and both can be dangerous, but they are surprisingly different. A hurricane is a vast storm that can stretch hundreds of kilometres across and last for many days. A tornado is a small, fierce, twisting column of air that is usually only tens or hundreds of metres wide and may last just minutes. Understanding how each one forms shows why they behave so differently.

Both belong to the family of powerful natural events you can read about in our lesson on floods, droughts and storms.

How a hurricane forms

A hurricane is a giant heat engine powered by the ocean. It needs a few key ingredients:

Warm ocean water, at least about 26.5°C, usually in late summer and autumn when the sea is warmest.
Moist, rising air. Warm seawater evaporates, and the warm, wet air rises.
A starting spin, provided by the rotation of the Earth.

As warm, wet air rises over the ocean, it cools and its water vapour condenses into clouds and rain. Condensation releases heat, which warms the surrounding air and makes it rise even faster. This rising air leaves an area of low pressure near the sea surface, and more air rushes in to fill the gap. As that air spirals inward, the storm grows and begins to spin.

Why does it spin instead of flowing straight in? Because the Earth is rotating. This deflects moving air — a phenomenon called the Coriolis effect — so the inrushing air curves into a great spiral. In the Northern Hemisphere hurricanes spin anticlockwise; in the Southern Hemisphere they spin clockwise.

At the very centre is the eye, a calm, often clear zone where air gently sinks. Around the eye is the eyewall, a ring of towering thunderclouds with the storm's strongest winds and heaviest rain.

A hurricane keeps its strength only while it sits over warm water. Once it moves over land, it is cut off from its fuel and begins to weaken — though it can still bring destructive winds, flooding rain and a surge of seawater pushed onto the coast, called a storm surge.

Measuring hurricanes

Scientists rate hurricanes using the Saffir-Simpson scale, from Category 1 (winds around 119 km/h) up to Category 5 (winds above 252 km/h). Higher categories mean more dangerous winds and damage.

A real example is Hurricane Katrina in 2005, which struck the southern coast of the United States. Its storm surge flooded much of the city of New Orleans, causing terrible damage and showing how the rising seawater — not just the wind — can be a hurricane's deadliest part. Forecasters now track storms for days in advance so that people can be warned and, if needed, evacuated.

How a tornado forms

A tornado is born not over the ocean but inside a severe thunderstorm on land. The storms most likely to spawn tornadoes are powerful, rotating thunderstorms called supercells.

Tornadoes form when there is wind shear — winds blowing at different speeds and directions at different heights. This sets a tube of air rolling horizontally, like a spinning pencil lying on its side. Strong updrafts inside the thunderstorm can then tilt this spinning tube upright. If the spin tightens and stretches down from the cloud base to the ground, a tornado forms: a violently rotating funnel of air connecting the storm cloud to the surface.

Tornadoes are small but extremely intense. The fastest tornado winds ever measured were over 480 km/h — faster than any hurricane. Because they are narrow, a tornado might flatten one house while leaving the one next door almost untouched.

You can see why both storms need clouds and rising air by exploring how storm clouds work in our lesson on thunder and lightning.

Measuring tornadoes

Tornadoes are rated on the Enhanced Fujita (EF) scale, from EF0 (weak, minor damage) to EF5 (incredible, total destruction of strong buildings). Because tornado winds are hard to measure directly, the rating is based mainly on the damage the tornado leaves behind. The central United States has a region nicknamed Tornado Alley, where warm, moist air from the Gulf of Mexico meets cool, dry air from the north, producing many strong tornadoes each year.

Comparing the two

Feature	Hurricane	Tornado
Size	Hundreds of km wide	Tens to hundreds of metres wide
Forms over	Warm tropical oceans	Land, inside thunderstorms
Energy source	Warm ocean water	Severe thunderstorm / wind shear
How long it lasts	Days to weeks	Minutes to about an hour
Measured by	Saffir-Simpson scale	Enhanced Fujita (EF) scale
Warning time	Often days	Often only minutes

Staying safe

For hurricanes, people follow forecasts, protect windows, store water and food, and evacuate the coast if officials advise it. For tornadoes, the safest place is a basement or a small, windowless room in the middle of a sturdy building, away from windows. In both cases, listening to official weather warnings saves lives, because modern forecasting gives people time to prepare.

Activity: track a storm season

Try this weather-watch research project.

Choose a current or recent hurricane or tornado season and follow it using a national weather service website (for example, the National Hurricane Center or a national meteorological office).
For a hurricane, make a simple map. Each day, plot the storm's position and write down its category and wind speed. Watch how it moves and how it strengthens over warm water and weakens over land.
For tornadoes, keep a tally of how many are reported in a week and their EF ratings, and note what kind of weather (warm, humid, stormy) came before them.
Keep a daily log of your own local weather too — temperature, wind, cloud type and air pressure if you have a barometer. Falling pressure often warns that a storm is approaching.
After a few weeks, write up what you learned about how, when and where these storms form. You will be doing exactly what real meteorologists do: watching the weather closely to understand and predict it.

Hurricanes and Tornadoes

Key takeaways