Hurricanes are violent storms that develop from cyclones that form over a tropical ocean. The cyclone will pass through two stages before it becomes a hurricane. The first stage is a tropical depression. The next stage is a tropical storm and then it becomes a hurricane. In order for the storm to be called a hurricane the winds must exceed more than 75 mph.
The diameter of a hurricane can vary from 25 to 600 miles wide and it can travel at speeds 10 to 30 mph. Wind speeds can blow from 75 to over 200 mph. In the center of the hurricane, known as the eye, the winds are very calm. The eye can measure from 20 miles in diameter. Hurricanes can cause tremendous coastal damage. They need warm water to form and keep going so hurricanes break up over land. Hurricane season is between July and October for the USA. One out of three hurricanes reaches the United States. The most commonly used scaleto measure the intensity of a hurricane is the Saffir Simpson Scale that rates hurricanes on a scale of 1-5. The most damaging hurricane in the United States was Hurricane Hugo. It hit mainland on September 21-22, 1989. It hit a number of islands in the Caribbean and it made landfall at Sullivan Island, northeast of Charleston, SC. On crossing the mainland, Hugo measured four on the Saffir Simpson Scale. Winds measured 135mph and 28 people were killed. The greatest number of fatalities from a hurricane is an estimated 6,000 deaths on September 8, 1900 in Galveston Island, TX.
A hurricane is formed when a cyclone forms in late summer or early autumn over a tropical ocean where the water is above 80 F. The warm, moist air will rise rapidly letting the cooler air move in. Then the air will begin to spin and the air pressure in the center will drop. More air will get sucked in and the air will spin faster. Then the rapidly spinning air will rise into the shape of a doughnut and carry strong winds, rain, and clouds. Now a hurricane is formed.
The weather service tracks hurricanes by using satellites to get pictures of early cloud formations. As it starts to get bigger, stronger, and closer to land the weather people will send out planes to see how it's formed, its wind speed, and in which direction it is heading. For safety, the weather station will send out warnings well in advance.
