Five things that a hurricane needs Click on image for full size (36 Kb) Lisa Gardiner/Windows to the Universe

One in a while, a tropical thunderstorm grows and grows, becoming a giant hurricane. First the storm grows a little bit. It combines with other thunderstorms and they all spin around an area of low pressure. This is called a tropical depression. Then the storm grows some more. Its winds become stronger and it is called a tropical storm. Then, the storm grows even more, its winds become even faster, and it is called a hurricane.

Hurricanes get their energy from the warm ocean water. When a hurricane is over warm water it will grow. A hurricane dies when it moves away from the warm water. When a hurricane moves into areas with cooler ocean water, it weakens. It will also weaken if it travels over land.