A hurricane is a tropical cyclone that has winds of 119 kilometers per hour or higher. A typical hurricane is about 600 kilometers across. Hurricanes form in the Atlantic, Pacific, and Indian oceans. In the western Pacific Ocean, hurricanes are called typhoons.
How hurricanes form
A typical hurricane that strikes the United States forms in the Atlantic Ocean north of the equator in August, September, or October. A hurricane begins over warm ocean water as a low-pressure area or tropical disturbance. If the tropical disturbance grows in size and strength it becomes a tropical storm which may then become a hurricane. A hurricane draws its energy from the warm humid air at the ocean's surface. As this air rises and forms clouds more air is drawn onto the system. Inside the storm are bands of very high winds and heavy rains. Winds spiral inward toward the area of lowest pressure at the center. The lower the air pressure at the center of a storm the faster the winds blow toward the center. Hurricane winds may be as strong as 320 kilometer per hour. Hurricane winds are strongest in a narrow band around the center of the storm. At the center is a ring of clouds called the eyewall that enclosed a quiet eye. The wind gets stronger as the eye approaches. When the eye arrives the weather changes suddenly. The air grows calm and the sky may clear. After the eye passes the storm resumes but the wind blows from the opposite direction.
How Hurricane move
Hurricanes last longer than other storms usually a week or more. During that period they can travel quite a distance. Hurricanes that form in the Atlantic Ocean are steered by easterly trade winds toward the Caribbean islands and the southeastern United States. After a hurricane passes over land it no longer has warm moist air to draw energy from. The hurricane gradually loses strength although heavy rainfall may continue for several days.
When a hurricane comes to ashore it brings high waves and severe flooding as well as wind damage. Low pressure and high winds of the hurricane over the ocean raise the level of the water up to 6 meters above normal sea level. the result is a storm surge is a dome of water that sweeps across the coast where the hurricane lands. Storm surges can cause great damage washing away beaches and destroying buildings along the coast and eroding the coastlines.
Until the 1950s a fast moving hurricane could strike with little warning. People now receive information well in advance of an approaching hurricane. A hurricane watch indicates that the hurricanes conditions are possible in an area within the next 36 hours. You should be prepared to evacuate is to move away temporarily. A hurricane warning means that hurricane conditions are expected within 24 hours. If you hear a hurricane warning and are told to evacuate and leave the area immediately.