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Cyclone Origins
Fri Sep 16, 2005
Listen in RealAudio 
Cyclone, the word has struck awe and dread in the hearts of many facing its fury, but
technically, it is only a swirl of counterclockwise wind around a low pressure center. It was
coined halfway around the world, in the Indian city of Calcutta.
While serving as President of the Marine Court of Calcutta, Henry Piddington, a former sea
captain, studied the stormy weather of the Indian Ocean. He focused particularly on the
devastating tropical storm of December 1789, which inundated the coastal town of Coringa with
three monstrous storm waves that killed more than 20,000 people.
In a presentation to the Asiatic Society of Bengal around 1840, Piddington described that
storm as a "cyclone," a term derived from the Greek word "kyklon" which means moving in a
circle, like the "coil of the snake."
Piddington introduced the word to mariners in his 1848 book "The Sailor's Horn-Book for the
Law of Storms". In the book, he warned sailors that the storms in the Bay of Bengal blew with
counterclockwise winds. The book included transparent storm cards with wind arrows that a
captain could use to set a course toward safer waters by sailing with the wind and then out of
harm's way.
The term quickly gained acceptance, but then received much broader usage. By 1856, the term
was used to describe the storms we now call tornadoes: such as the famous Kansas Cyclone from
"The Wizard of Oz". In 1875, the international meteorological community adopted the term to
describe any low pressure system with counterclockwise wind field. Northern Hemispheric High
pressure systems are called "anticyclones". But even today, tropical storms of the Indian
Ocean are still called Cyclones.
Thanks to our contributing writer, meteorologist Keith Heidorn. Check out past Weather
Notebook stories at www.weathernotebook.org. We are funded by Subaru, and The National Science
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