Giant Storms of the Sea
A hurricane is one of the most powerful storms on Earth: a vast, swirling system of clouds and wind, sometimes hundreds of kilometers across, capable of bringing destructive winds, heavy rain, and dangerous flooding to entire coastlines. Unlike a quick thunderstorm, a hurricane can last for many days as it travels across the sea. These storms do not appear suddenly. They are born from a very specific set of conditions over warm tropical oceans, and they grow step by step.
Warm Ocean Water Is the Fuel
The first ingredient a hurricane needs is warm ocean water, usually at least 26 degrees Celsius, reaching down a fair depth below the surface. This warm water acts as the storm's fuel. The Sun heats the surface of the ocean, and the heat causes water to evaporate into the air above, filling that air with invisible water vapor. As this warm, moist air rises, it cools higher up and the water vapor condenses into clouds, releasing more heat in the process. That released heat warms the air further and makes it rise even faster, pulling in still more warm, moist air from below.
Spinning Air Becomes a Storm
A second ingredient is needed to turn rising air into a hurricane: rotation. Because the Earth is spinning, air that moves over long distances on the planet's surface gets gently turned. This effect is too weak right at the equator, but a little further away from it, it is enough to set huge weather systems slowly rotating. As warm air rushes in toward the area of rising air, this rotation organizes the wind into a curving, spiraling pattern, and a tropical disturbance can grow into a more organized spinning storm.
Building Into a Hurricane
If conditions stay favorable, with warm water, plenty of moisture, and not too much disruptive high-altitude wind, the storm can keep strengthening. The spinning system tightens, winds blow harder, and bands of thunderstorms wrap around a central low-pressure core. Eventually, an eye forms at the center, a calm, clear region surrounded by the storm's most violent winds in a ring called the eyewall. Once the sustained winds reach a certain strength, the storm is officially called a hurricane. When a hurricane moves over cold water or onto land, it loses its source of warm-water fuel and gradually weakens.
Source
This article was written using information from Wikipedia.