What is the lowest ocean temperature at which a tropical cyclone can form?

27 °C. The sea must be at least 27 °C.

Between which latitudes do tropical cyclones form?

5° and 30°. North or south of the Equator.

Which is another name for a tropical cyclone?

typhoon. Storm, hurricane and typhoon all mean the same.

What is the least depth of ocean needed?

60 m. A deep layer of warm water keeps the storm supplied.

How are tropical cyclones monitored?

with satellites. Satellites show where the storm is and where it is heading.

Why does a tropical cyclone weaken when it moves over land?

it is cut off from the warm ocean water that powers it. No warm sea means no evaporation to feed it.

Tropical cyclones · Cambridge IGCSE Environmental Management

In plain words

Cyclone, hurricane, typhoon: three names for the same thing, in different oceans. It is a spinning storm hundreds of kilometres across, fed by warm sea water, and it needs a precise set of conditions before it can form at all.

9 things to know

A tropical cyclone is a large, rotating storm with very strong winds and heavy rain. Tropical cyclones are also called storms, hurricanes and typhoons.
They form between 5° and 30° of latitude, north or south of the Equator.
The ocean temperature must be at least 27 °C, and the ocean must be at least 60 m deep. Warm water evaporates, and the rising moist air powers the storm.
Impacts: damage to buildings and infrastructure; loss of crops, livestock and habitats; and the evacuation of people and livestock.
Heavy rain, and sea water pushed onto the land by the wind, cause flooding. Rain on steep slopes causes landslides.
Drinking-water supplies are contaminated, which brings water-related disease. There are financial losses, and human health suffers through deaths, injuries and stress.
Before: monitoring and warning, using satellites to track the storm for days. Buildings are given structures that stand up to wind and flood. Disaster preparation means plans, drills, emergency supplies and emergency rescue teams.
During and after: evacuation, shelters, the rebuilding of damaged areas, and international aid.
Limitations. A storm can change direction, so warnings are sometimes wrong, and then people stop trusting them. Strong buildings and shelters cost money. Some people will not leave their homes and animals.

Worked example

Explain why tropical cyclones do not form over the sea around northern Europe.

They need an ocean temperature of at least 27 °C. The sea around northern Europe is much colder than that.
They form between 5° and 30° of latitude. Northern Europe is much further from the Equator.
Without warm water there is too little evaporation to power the storm.

Tips and tricks

Learn the four numbers: 5° to 30° of latitude, at least 27 °C, at least 60 m deep.
Tropical cyclones can be tracked for days by satellite. That is the big difference from earthquakes, and it is why evacuation saves so many lives.

6 questions, about 2 minutes.

It lands in your notebook with its questions as flashcards.

Tropical cyclones: 6 questions and answers

These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.

What is the lowest ocean temperature at which a tropical cyclone can form?
- 17 °C
- 21 °C
- 27 °C (the answer)
- 37 °C
The sea must be at least 27 °C.
Between which latitudes do tropical cyclones form?
- 0° and 5°
- 5° and 30° (the answer)
- 30° and 60°
- 60° and 90°
North or south of the Equator.
Which is another name for a tropical cyclone?
- tornado
- tsunami
- monsoon
- typhoon (the answer)
Storm, hurricane and typhoon all mean the same.
What is the least depth of ocean needed?
- 60 m (the answer)
- 6 m
- 600 m
- 6000 m
A deep layer of warm water keeps the storm supplied.
How are tropical cyclones monitored?
- with pitfall traps
- with quadrats
- with satellites (the answer)
- with seismometers
Satellites show where the storm is and where it is heading.
Why does a tropical cyclone weaken when it moves over land?Stretch
- the land is at a higher latitude
- the wind cannot blow over land
- the air pressure rises to normal at once
- it is cut off from the warm ocean water that powers it (the answer)
No warm sea means no evaporation to feed it.

6 questions

Tap an answer and you’ll see straight away whether it’s right, and why.

Worksheet

3 questions, 8 marks. Write your answers on paper, then check them.

Tropical cyclones

Cambridge IGCSE Environmental Management 0680 · 8 marks · papermunch.org

Name ______________________________ Date ______________

State the conditions needed for a tropical cyclone to form.[3]
Show answerHide answer
A latitude between 5° and 30° north or south of the Equator. An ocean temperature of at least 27 °C. An ocean depth of at least 60 m.
I got this one
Describe three impacts of a tropical cyclone on people.[3]
Show answerHide answer
Any three: buildings and infrastructure are damaged; crops and livestock are lost; people are evacuated; flooding and landslides occur; drinking water is contaminated and disease spreads; there are financial losses; people are killed or injured.
I got this one
Explain why monitoring is an effective strategy for tropical cyclones.[2]
Show answerHide answer
Satellites track the storm for days before it reaches land. Warnings can be given in time for people to prepare or evacuate.
I got this one

Answers: Tropical cyclones

1. A latitude between 5° and 30° north or south of the Equator. An ocean temperature of at least 27 °C. An ocean depth of at least 60 m.
2. Any three: buildings and infrastructure are damaged; crops and livestock are lost; people are evacuated; flooding and landslides occur; drinking water is contaminated and disease spreads; there are financial losses; people are killed or injured.
3. Satellites track the storm for days before it reaches land. Warnings can be given in time for people to prepare or evacuate.