posted Sep 22, 2014, 8:35 PM by Tom Kachelman
updated Sep 22, 2014, 8:36 PM
The term "hurricane" is derived from "Taino", a native american word which means evil spirit of the wind. In short hurricanes are engines of destruction and a huge hurricane can release energy equivalent to 10 atomic bombs per second.
The Saffir-Simpson Hurricane Scale defines hurricane strength by categories. A Category 1 storm is the weakest hurricane with winds having speed between 74-95 mph; a Category 5 hurricane is the strongest with winds greater than 155 mph.
Hurricanes are giant, spiraling tropical storms that can pack wind speeds of over 160 miles (257 kilometers) an hour and unleash more than 2.4 trillion gallons (9 trillion liters) of rain a day.
These same tropical storms are known as cyclones in the northern Indian Ocean and Bay of Bengal, and as typhoons in the western Pacific Ocean.
Hurricanes begin as tropical disturbances in warm ocean waters with surface temperatures of at least 80 degrees Fahrenheit (26.5 degrees Celsius).
These low pressure systems are fed by energy from the warm seas. If a storm achieves wind speeds of 38 miles (61 kilometers) an hour, it becomes known as a tropical depression. A tropical depression becomes a tropical storm, and is given a name, when its sustained wind speeds top 39 miles (63 kilometers) an hour. When a storm’s sustained wind speeds reach 74 miles (119 kilometers) an hour it becomes a hurricane and earns a category rating of 1 to 5 on the Saffir-Simpson scale.
Hurricanes are enormous heat engines that generate energy on a staggering scale. They draw heat from warm, moist ocean air and release it through condensation of water vapor in thunderstorms.
Hurricanes spin around a low-pressure center known as the “eye.” Sinking air makes this 20- to 30-mile-wide (32- to 48-kilometer-wide) area notoriously calm. But the eye is surrounded by a circular “eye wall” that hosts the storm’s strongest winds and rain.
These storms bring destruction ashore in many different ways. When a hurricane makes landfall it often produces a devastating storm surge that can reach 20 feet (6 meters) high and extend nearly 100 miles (161 kilometers). Ninety percent of all hurricane deaths result from storm surges.
Interactiv graphic credits BBC