6.2 Tropical Cyclones

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What is a Tropical Cyclone?

A tropical cyclone is an enormous, spinning storm system that forms over warm tropical oceans. It brings very strong winds, very heavy rainfall, and can cause huge amounts of damage when it reaches land.

Tropical cyclones are known by different names depending on where in the world they occur:

• Hurricane — in the North Atlantic Ocean and the northeastern Pacific Ocean (e.g. affecting the Caribbean, USA, and Mexico)
• Typhoon — in the northwestern Pacific Ocean (e.g. affecting the Philippines, Japan, and China)
• Tropical cyclone — in the Indian Ocean and the southwestern Pacific Ocean (e.g. affecting India, Bangladesh, and Australia)

They are the same type of storm — just with different regional names.

Distribution of Tropical Cyclones — Where Do They Form?

Distribution means the pattern of where something is found around the world.

Tropical cyclones form in a specific belt around the Earth — roughly between 5° and 20° north and south of the Equator (the Equator is the imaginary line at 0° latitude that divides the Earth into the Northern and Southern hemispheres).

This means tropical cyclones form in the tropics — the warm zone close to the Equator. They do not form:

• Right on the Equator (at 0°) — because a force called the Coriolis effect (explained below) is too weak there to make the storm spin.
• Far away from the Equator (beyond about 20°) — because the ocean water becomes too cold to power the storm.