We call them hurricanes. People in other parts of the world call them typhoons or cyclones. But they are all the same thing: a rotating storm that forms in the tropics (that’s near the equator) and has winds of at least 74 miles per hour.

“Hurricane” comes from Hurican, the name of an evil god for ancient peoples of the Caribbean. They took the name from Hurakan, the name the ancient Maya of Mexico gave to their god of wind and storm. For people in the tropics, these storms have always been a part of life.

Hurricane Formation
How does a hurricane form? It’s complicated. But it all boils down to the sun’s heat and the earth’s rotation. If all the conditions are right, these two ingredients can turn a simple thunderstorm into a fierce, swirling hurricane.

Meteorologists monitor the development of tropical thunderstorms to judge when they might become a serious threat. They have created a ranking system to track hurricane development:

1. A tropical disturbance is created when several large thunderstorm clouds form and cluster together.
   
   
2. A tropical depression develops when the earth’s rotation causes the winds of a tropical disturbance to begin swirling around its center.
   
   
3. A tropical storm forms if the winds reach 39 miles per hour.
   
   
4. A hurricane grows when wind speeds reach 74 miles per hour.
   

Hurricane Anatomy
A hurricane has three main parts. The eye is the storm’s low-pressure center. Around the eye, the eye wall has the storm’s most violent winds, as well as torrential rains. Thunderstorms spiraling outward from the center become the rain bands that make up the rest of the storm’s structure.

As long as the hurricane stays over warm ocean waters, it can grow until it reaches hundreds of miles in diameter. It falls apart only if it moves over land, which cuts off its water supply.


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