As one of nature's most destructive forces, it is fitting that the hurricane is named after the Carib god of evil, Hurican. The name can also be traced back to a Mayan creation legend, where the god Hurakan blew his breath across chaotic ocean waters to uncover dry land.

The association with both evil and creation proves the fear and awe the deadly phenomenon has long inspired, and not without reason. Alternatively known as a jimmycane, haurachana, or hurleblast, among dozens of other names, the hurricane is a broad, well-defined system of powerful thunderstorms rotating around a center, or eye.

The storm's center usually ranges from 20 to 40 miles across and is relatively calm, with light winds and no rain. The eyewall - the ring of thunderstorms closest to the storm's eye - are typically where the storm's most violent winds and rain occur.

Along with tropical storms and tropical depressions, hurricanes are a type of tropical cyclone. While each of these three types of tropical cyclones is a system of thunderstorms, hurricanes have the most powerful winds - at least 74 mph - and generally inflict the most damage.

Hurricanes sometimes produce tornadoes, which usually develop away from the center of the hurricane and can pose an additional threat, although they tend to be relatively weak and short-lived.

Hurricane season
The Atlantic hurricane season runs from June 1 through the end of November, with storms posing the greatest risk to the U.S. East Coast between mid-August and mid-October. In the Atlantic, Caribbean and Gulf of Mexico, conditions are ripe for storms to develop during these months. In other parts of the world, typhoons and cyclones, which are equivalent to hurricanes in strength and structure, but originate in different oceans, occur at other times of the year.

Two conditions spur a hurricane's development: A tropical climate, which provides a breeding ground for thunderstorms; and warm ocean waters, which give storms energy. Another factor, easterly waves - low-pressure weather systems moving from east to west and causing a shift in winds and rain - often spark hurricanes. These storms, which originate over North Africa and occur between April and November, can develop into hurricanes if they travel over water that is at least 80 degrees Fahrenheit, and if they do not come into contact with high winds. An easterly wave can prosper in these conditions, and the storm will then be steered by capricious winds.

According to the National Weather Service, an average of ten tropical storms develops in the Atlantic Ocean each year, of which six become hurricanes. In an average three-year period, five hurricanes hit the U.S. East Coast.

Measuring a storm's intensity
A hurricane's strength is categorized according to the Saffir-Simpson scale. Developed in 1969 by Herbert Saffir and Dr. Bob Simpson, it is designed as an "estimate of the potential property damage and flooding expected along the coast from a hurricane landfall," according to the National Weather Service. The scale gives storms a rating of 1 through 5, based on their sustained wind speed.

A Category 1 storm carries winds of 74 to 95 mph and poses no significant threat to buildings, but can down trees and cause some coastal flooding. With winds from 96 to 110 mph, Category 2 storms can blow down trees, and damage roofs, windows and doors. Small buildings and roofs are vulnerable in Category 3 storms, which pack winds from 111 to 130 mph and can fell large trees and destroy mobile homes. Category 4 storms bring winds from 131 to 155 mph and can cause extensive damage to roofs, windows and doors. The most intense storms are rated level 5, and have wind speeds greater than 155 mph and can destroy roofs or entire buildings and cause major flooding.

While the Saffir-Simpson scale rates storms solely on the basis of wind speed, often much of the damage a hurricane causes is from flooding. The coast is particularly vulnerable to a hurricane's storm surge - the abnormally high sea level caused by winds pushing the ocean surface ahead of the storm. That dome of water is often 50 to 100 miles wide and can combine with a high tide to cause even more damage. With a high tide and a storm surge, a hurricane can cause the average water level in the ocean to rise up to 15 feet. According to the National Hurricane Center, much of the densely populated Gulf Coast and Atlantic coastlines are less than 10 feet above sea level, putting them at great risk during a hurricane.

When hurricanes first reach land, the storm's short wind gusts become stronger, but the average wind speed begins to decrease. A few hours after reaching land, the storms weaken significantly because the ocean is no longer providing heat and moisture as fuel.

-- By Karyn Schwartz, Online NewsHour