GCSE · Geography · AQA · Spec 8035

Causes and formation of tropical storms

Hurricane, cyclone, typhoon: three names, one kind of storm. They are all tropical storms, and they share one weakness. Take away the warm ocean underneath and they fade.

History · Cause & effect

One storm, three stages

Tap 01, then 02, then 03. At each stage, read what led to it on the left and what it leads to on the right.

Causes ←

What led here

The storm has moved off the ocean and over land

It has lost its energy source: the heat and moisture of warm ocean water

Event

Weakens and dissipates

Over land

Once the storm moves over land, the warm ocean is no longer beneath it. It has lost its energy source, so it weakens and in time dissipates, which means it fades away.

→ Consequences

What followed

The storm weakens

It dissipates: it fades away and dies out

What do you think?

The storm reaches the coast

A tropical storm has been intensifying over the ocean. Now it is crossing the coast and moving over land.

Which is closest to what you think happens to it next?

Not much changes. Once a storm is going, it carries its own power with it.It gets stronger. Land is where a tropical storm is at its most powerful.It starts taking its energy from the land instead, so it keeps going.It weakens, because it is no longer over the warm ocean water that was giving it energy.

How sure are you?

I'm sureI think soI'm guessing

Not much changes. Once a storm is going, it carries its own power with it.

This is a common misconception

This is the idea most worth letting go of. A tropical storm is not like a battery that brings its energy along. Its energy comes from the heat and moisture of the warm ocean water underneath it. Over land that supply is gone, so the storm weakens.

It gets stronger. Land is where a tropical storm is at its most powerful.

This is a common misconception

It is the other way round. The strengthening happens over the ocean, while warm water is feeding the storm. That is the intensifying stage. Over land the storm has lost its energy source, so it weakens rather than grows.

It starts taking its energy from the land instead, so it keeps going.

This is a common misconception

Land cannot take over the job. The storm's energy comes from the heat and moisture of warm ocean water, and once it is over land it has lost that energy source. There is no swap to a new supply, which is why it weakens.

It weakens, because it is no longer over the warm ocean water that was giving it energy.

This matches the evidence

Exactly right. Over land the storm loses its energy source, the heat and moisture of warm ocean water, so it weakens. Without that supply it goes on to dissipate.

Over the ocean, the storm is fed and can grow. Over land, it is cut off from its energy source and weakens.

Words you'll use

Say the meaning out loud before you reveal each card.

Your turn

Follow a storm's journey

A tropical storm travels across the open ocean, then crosses a coastline and moves inland. Explain how its strength changes during this journey. [4 marks]

Your answer

0 words · your answer stays on this page and is not sent anywhere.

The mark scheme

Over the ocean it draws energy from the heat and moisture of the warm water. (1 mark)
So it intensifies (gets stronger) while it is travelling across the ocean. (1 mark)
Inland it has lost its energy source, because the warm ocean is no longer beneath it. (1 mark)
So it weakens, and eventually dissipates. (1 mark)

Model answer

While the storm is over the open ocean, it draws energy from the heat and moisture of the warm water, so it intensifies and grows stronger as it travels. Once it crosses the coastline and moves inland, the warm ocean is no longer beneath it, so it has lost its energy source. As a result it weakens, and eventually it dissipates.

The storm's strength follows its energy supply: fed over the ocean, cut off over land. Say that link out loud at each point of the journey and the explanation writes itself.

Exam line: Explain means give reasons. Use 'so' and 'because' to link each change in strength to what the energy supply is doing.

WHAT YOU'VE LEARNED

A quick recap of today's lesson.

Follow one storm from warm ocean to land, and keep asking one question: what is feeding it now?

What you need to know

Hurricanes, cyclones and typhoons are all names for tropical storms.
Tropical storms develop as a result of particular physical conditions.
They form over warm ocean water and draw energy from its heat and moisture.
The sequence: they form in source areas, intensify as they track over oceans, then dissipate.
Once over land, they lose their energy source and weaken.

The big picture

Tropical storms (also called hurricanes, cyclones and typhoons) develop when particular conditions come together. They form in source areas over warm ocean water, where they draw energy from the heat and moisture. They intensify as they track over the ocean, then weaken once they move over land and lose their energy source, and finally dissipate.

Key points

1A tropical storm's energy comes from the heat and moisture of warm ocean water.

2It forms in a source area over warm ocean water, when particular conditions come together.

3It intensifies (gets stronger) while it tracks over the ocean and keeps drawing on that energy.

4Over land it loses its energy source, so it weakens and then dissipates.

5Hurricane, cyclone and typhoon are different names for the same kind of storm.

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Worked example

Problem

Two tropical storms are on the map. Storm A is still tracking over warm ocean water. Storm B has just crossed the coast and is now over land. Which storm is more likely to be intensifying, and why?

⚠ Watch out

Writing 'tropical storms form because it is hot'. That is too vague to explain anything. Say where the energy comes from: the heat and moisture of warm ocean water.

🧠

Memory hook

Ocean feeds it, land starves it. Form, grow, fade.

✓

Check yourself

Cover the page. In two sentences, explain why the same tropical storm can be intensifying at one point on its track and weakening at another.

Flashcards

(7)

What are hurricanes, cyclones and typhoons?

All tropical storms: different names for the same kind of storm.

Where do tropical storms form?

In source areas over warm ocean water.

Where does a tropical storm get its energy?

From the heat and moisture of warm ocean water.

What happens to a tropical storm as it tracks over the ocean?

It intensifies (gets stronger), because it keeps drawing energy from the warm water.

Why does a tropical storm weaken once it reaches land?

Land cuts it off from the warm ocean, so its supply of heat and moisture is gone.

Put the stages of a tropical storm's life in order.

Forms in a source area → intensifies as it tracks over the ocean → dissipates.

What does 'dissipate' mean?

To fade away and die out: the final stage of a tropical storm's life.

Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.

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One storm, three stages

The storm reaches the coast

Follow a storm's journey

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