Violent winds, driving rain, killer waves. These are the hallmarks of a hurricane,also called cyclones or typhoons, hurricanes are giant storms prowling the world's tropical seas. An average hurricane releases as much energy in a day as the explosion of half a million small atomic bombs. Hurricanes form in the Summer and Fall when the sun heats vast stretches of tropical ocean to over 82 degrees.
More moisture rises over these hot spots creating thunder storms. Upper level winds and surface winds then come together forming a circular pattern of clouds known as a tropical depression. When the winds exceed 39 miles per hour, a tropical storm has developed. When the winds reach 74 miles per hour a hurricane is officially born.
Inside the storm bands of the rain up to 300 miles long meet in the eye wall, the most violent section. Here winds of up to 200 miles per hour spiral upword within the centre of the hurricane down drafts of dry air create a strangely calm area called the eye. Fully formed a hurricane may stretch over 500 miles in a diameter. That is a storm nearly the size of Texas and reach a height of 9 miles.
Most of the storm spin out over the open sea but in an average year 2 or 3 will strike the main land of North America and when they do the damage can be catastrophic. Most dangerous is the storm search. A wall of water that sweeps across the coastline where hurricane makes land fall. About 45 thousands of people were killed by hurricanes in 20th century including some 15 thousand in the USA.
Hurricanes are also costly in dollars. 1992's hurricane Andrew was the most expensive natural disaster in U.S history causing more than 25 billion dollars worth of damage. Scientists are searching for better ways to predict the path of a hurricane.
Special planes called hurricane hunters fly directly into these monster storms and drop sensors to measure wind speed, temperature, and air pressure providing vital clues to the hurricane's direction. New 3D models are also helping scientists understand this awesome force of nature and provide quicker and more accurate warnings to anyone unlucky enough to be caught in its path.