Hurricanes and Tornadoes - district87.org

Hurricane as a System
Thunderstorms move toward the area with the lowest air
pressure. They move in a spinning pattern. A lot of air moves
out of the top of the storm. Less air moves in at the surface of
the ocean. Air pressure keeps dropping. This makes the winds
blow even faster. When the wind speeds reach 119 kilometers
per hour, the storm is a hurricane.
Parts that work together or affect each other make up a
system. The atmosphere and the ocean are two of Earth’s
systems. Together they produce a hurricane. Hurricanes are
systems. They form in the atmosphere. They get energy from
the ocean.
Hurricanes can change Earth’s systems. They can change the
land. They can cause huge waves. They can change the shape
of a coastline.
The Hurricane’s Eye
The eye of a hurricane is the calm area in the middle of the
storm. The hurricane spins around its eye. The winds in the
eye are gentle. The eye has little or no rain. The thunderstorms
around the eye have the strongest winds and heaviest rains. A
typical hurricane’s eye is about 20 to 50 kilometers across.
People under the eye may think the hurricane has passed.
They must be careful. They need to be in a safe place when the
other half of the hurricane sweeps in.
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