Information on Hurricanes, Tropical Storms & Tropical Depressions

Hurricanes can produce waterspouts.

Hurricanes, tropical storms and tropical depressions are all commonly known as tropical cyclones. A tropical depression is the weakest of the three, but a depression may strengthen into a tropical storm, which can then grow into a hurricane.

Definitions

Tropical cyclones in the North Atlantic are divided into three categories based on wind speed: tropical depressions, tropical storms and hurricanes. A tropical depression is a rotating complex of thunderstorms with wind speeds of less than 38 mph. A tropical storm possesses wind speeds between 39 and 73 mph, while a hurricane's winds reach 74 mph or more.

Life Cycle

In the North Atlantic, tropical cyclones generally occur between June and November. All tropical disturbances begin as depressions, drawing their energy from warm ocean water. If a storm encounters cool water, land or strong wind shear, it weakens and dissipates.

Characteristics

These low-pressure systems rotate in a counterclockwise direction. Tropical storms may develop an eye, which is a calm, cloudless area of fair weather in the center of the storm. The most severe weather occurs along the edge of the eye wall.

Effects

Tropical cyclones produce torrential rains, high winds and storm surge. They can also spawn tornadoes and waterspouts.

References

• Atlantic Oceanographic and Research Laboratory: Hurricane Research Division
• USA Today: What Makes a Storm a Hurricane