Wind Storms: Cyclones .

A cyclone is a powerful, swirling wind storm. They occur frequently in North America, South Africa, Australia, and East Asia.

How they form: When air near the ground or sea heats up, it rises. To fill that empty space, surrounding air rushes in and begins to spin upward rapidly, carrying dust and debris. This creates a moving column of air that can knock down trees, houses, and electric poles.

Key Facts about Cyclones:

• Speed: Winds can travel faster than 170 km/h.

• Measurement: The intensity is measured on the Fujita Scale. "F-5" is the most powerful type.

• Direction: In the Northern Hemisphere, they spin counter-clockwise; in the Southern Hemisphere, they spin clockwise.

• Forecasting: Scientists use Doppler Radar to predict them.

• History: The deadliest cyclone in history occurred in Bangladesh (Manikganj) in 1989, killing 1,300 people.