Cyclones are huge storms. They happen over the Atlantic and Pacific Oceans. They can cause great damage when they hit land.

Cyclones form over warm ocean water. They only happen if there are moderate to strong winds blowing in the same direction at sea level. There also has to be a big difference between the atmospheric pressure t sea level and at higher levels.

When a storm becomes a cyclone, winds and clouds start twisting around an "eye". This is the centre of the storm. Everything is calm there. Cyclones twist anti-clockwise if they are in the northern hemisphere, and clockwise if they are in the southern hemisphere. Winds can blow as fast as 250km per hour. When a cyclone hits land, it can damage buildings, trees and cars.

A cyclone can be very dangerous. Thanks to satellites, scientists can spot them early and warn people who live near the coast about them.