hurricane is called a tropical eddy tower, if it develops in the Atlantic, in the Karibik, in the north Pacific east the date border or in the south Pacific east of 160° O. The word hurricane originally comes from Indianiand as much means as „God of the wind “(see also Huracan).

Other names for tropical eddy towers are cyclone (India), Taifun (in the western Pacific) or tropical cyclone (Australia); the term Willy Willy occasionally which can be found in German literature designates a Kleintrombeand no tropical eddy tower.

A tropical eddy tower becomes the hurricane, if the wind velocity gale strength reached (more than 118 km/h or wind force correspond to 12 on the Beaufort's scale). They can expand in the diameter of hundreds kilometers, exist for weeks andSurfaces of thousands square kilometers devastate. Hurricanes develop on the northern hemisphere in the time of May until December, most between July and September. The official season lasts from the 1. June up to 30. November.

The high wind velocities, waves and heavy precipitation represents a large danger. Caused the highest material damage in August 2005 the hurricane Katrina with approximately 125 billion dollar (100 billion euro), that with wind velocities from 250 to 300 km/h over Florida, Louisiana(particularly the region new Orleans), Mississippi, Alabama and Tennessee pulled away and over thousand victims demanded.Katrina raved on over 233,000 square kilometers; this corresponds nearly to the surface of Great Britain. Approximately 350,000 houses were destroyed. The damage sum is more largely than those thattwelve next-heavy hurricanes together taken and about five times as largely as the damage caused by hurricane Andrew 1992.

The strongest hurricane measured to date was Wilma, which as the first within fewer hours of a tropical storm (113 km/h, 18. October2005) to a hurricane of the category 5 (282 km/h, 19. October 2005 was up-gradated). With 882 millibars Wilmas the lowest air pressure in the center, which was ever measured on the Atlantic, prevailed.

If hurricanes reach the Frontalzone of the middle widths, can they into a non-tropical low pressure system are converted (extratropical transition) and then even still Europe heavy rainfalls bring.

Satellitenbild des Hurrikans Mitch
Satellite photograph of the hurricane Mitch
Satellitenbild des Hurrikans Katrina
satellite photograph of the hurricane Katrina

the development of a forthcoming hurricane season can be predicted by means of a weather prognosis.

Table of contents

Developing way and life cycle

of hurricanes develop in principle over the sea with a water temperature of over 26,5°C. This temperature must be present also still in a depth of approximately 50 m. If an even temperature gradient to large heights a certain measure, a tropical eddy tower exceeds can be formed. The water evaporated in large quantities and the specifically lighter water vapour ascends into large heights, where by condensation large thunderclouds are formed.

From ascending air masses results over the warm sea surfaceNegative pressure, from the environment flows air with a high water vapour portion. „A fire-place forms “, in which these air masses rise collected upward, while the high water temperatures constantly supply „food “. Ascending air masses become by the Corioliskraft in rotationshifted, a wide eddy develops.

Important conditions for the storm formation are:

  1. The sea must exhibit a surface temperature of at least 26.5 degrees and air an even temperature decrease to large heights (with very strong temperature decrease, those ascending the humidAir favoured, lower water temperatures can be sufficient; see also hurricane Vince).
  2. The area concerned of even conditions must be expanded, so that the moving eddy tower over longer time by the water vapour formation develop themselves and collect enough energy up to the strength of a hurricanecan.
  3. The distance from the equator must be large enough (at least 5 degrees of latitude or 550km), since only then the Corioliskraft is minted enough, in order to give to ascending air masses the typical turn.
  4. No large vertical wind shear may arise, i.e.,that to the emergence of a hurricane the elevator wind with similar strength and from the same direction blow must as the surface wind. This is the case does not get the ascending hoist an inclination and the mechanism of the storm cannot any longer function.
  5. The storm needs a Nucleus, of which it can compose itself, for example a non-tropical low.

developing places

of hurricane often develop within the range of the Caribbean sea, the westIndian islands and the gulf of Mexico. They developusually from disturbances of the trade wind, which always lie over warm sea areas.

With the hurricane Vince formed at the 9.Oktober 2005 for the first time since beginning of the weather recording 1851 a hurricane in the eastern Atlantic before the coasts of south Europe and North Africa. Vince formedbetween the Azores and the Kanaren, however still weakened itself before reaching the mainland on a storm low. The tropical storm delta, hurricane Epsilon, as well as the tropical storm Zeta likewise developed in the eastern Atlantic, with which in the year2005 for the first time, with Vince and delta, two eddy towers the coasts of Europe reached.

typical characteristics

typical is the so-called „eye “; a wind-free, dry and cloud-poor zone in the center of the hurricane. The passage of the eye in former times often becamewith the end of the storm confounds; Humans, who went meanwhile in the free, were surprised by the again breaking storm and fell him occasionally to the victim.

wind velocity

eye of the hurricane Katrina, taken up from a NOAA P-3 in accordance with

airplanethe definition after the Saffir Simpson scale one speaks D of a hurricane, if the wind velocity exceeds 118 km/h. h. Beaufort 12 reaches:

The Saffir Simpson hurricane scale
category wind in mph wind in km/h Flutwelle with the impact country (in m) central pressure in hPa
Tropical eddy tower 35-73 56-117 0-1
1 (weakly) 74-95 118-153 1-2 over 980
2 (moderately) 96-110 154-177 2-3 965-979
3 (strongly) 111-130 178-210 3-4 945-964
4 (very strongly) 131-158 211-249 4-6 920-944
5 (devastating) over 158 over 249 over 6 under 920

the destruction strength of a hurricane grows for instance with the third power of the wind velocity.

The resulting wind velocity above ground results from the movement of the center (course speed, see below) overlaid with the circulating rotation of the eddy, those within the range that Eyewall approximately around that nearly zero wind eye largest is. A hurricane with up to 100 km diameters can reach wind velocities of over 200 km/h; in the particularly endangered zones on the right of the course direction of a devastating hurricane of the category 5 becomealso 300 km/h exceeded.

process and behavior

from the wind velocity to to differentiate is the course speed of the hurricane. It is measured with the movement of the eye in relation to reason. Even if itself Atlantic of hurricane briefly after the emergence outweighingto the west to northwest and between that 20 often moves. and 25. Degree of latitude northward to northeast turn off, then this typical behavior is to be expected neither compellingly nor surely.

From quasi motionless hurricanes, weakening themselves by coolerSea water to the water surface brought, up to tänzelnden, rolling and loop-shaped processes above ground already everything one observed. Also eastward pulling eddy towers and unexpected short term changes of direction like sudden turning off after southwest are not to be excluded.

Hurricanes receive theirEnergy from the evaporation of the warm Oberflächenwassers. Meet they during their course on country - one speaks then of the Landfall - in such a way weaken themselves their supply at energy and them lose at strength. More deeply landinward convenient regions become thereforeof the wind velocity less violently met. Since in the hurricane catchment area in addition, large Wassermassen are in the clouds, the Abregnen of these clouds can bring also still hundreds of kilometers far away from the coast as tropical eddy tower gigantic amounts of precipitation with itself.

The forecast of the course direction and the strength of hurricanes is important, in order to warn and evacuate the population if necessary in the betroffenden regions in time.


of hurricanes possess three destruction causes. On the one hand the wind velocity, to second thoseAmounts of precipitation and to third the unequal weights in the atmosphere, caused by it in the peripheral area.

The high wind velocities can first directly by the impulse of air masses damage e.g. cause at buildings or trees. Due to the high speeds also heavy can Articles by air to be hurled, which for their part again damage can cause.

Over the sea by the strong wind the water high waves are produced. Besides the hurricane moves a tide mountain over before itself. There itself in the Northern HemisphereHurricane against the clockwise direction turns, is pronounced this tide mountain particularly in that quadrants, which are right from its direction of travel, because adds itself there the vectors of its course direction and the circulating hoist. With Landfall is therefore in this quadrants alsoto count heaviest floodings. Sometimes the tide mountain can accumulate ashore up to 10 m over NN (hurricane Katrina). Exceptions apply to small islands, over which only one part of the hurricane pulls away, or bays, in those thoseTide also in directions deviating from it to accumulate can.

By the continuous evaporation of warm Oberflächenwasser and condensation at the upper layer of the cloud system, large quantities of water are in the storm system, which can lead to extremely strong precipitation. Thereby inundations themselves can in areas lain more highly to be released.

In the eye of the hurricane cold air masses fall into the center from the sides. At the border of the eye of a strong hurricane therefore briefly Tornadoes can form. Their life span is usually only on secondsor minutes limited, its destruction potential is for it all the more violent.

rising threat potential

of hurricanes refer their energy from the warm Oberflächenwasser. During in the last decades the observed continuous heating up of the surface temperature stands therefore for more energy for educationfrom hurricanes to the order. It is scientifically not yet safe nevertheless whether in the future on ever stronger and more threatening hurricanes is to be counted. Some scientists are the opinion that by the global climatic changes to it must lead, concretely the rise of the average temperatureand thus the surface temperature of the Weltmeere. A study of the WITH, in which the hurricane activity of the last three decades is analyzed, confirms this tendency. On the other hand sea and deposits point on the fact that today's eddy towers are neither stronger nor more frequently appears than tooTimes of the Maya.

In opinion of professor Stefan cream peat, Institut for climatic research in potsdam, increases the number of eddy towers due to the heating up of the tropical seas not, very probably however their intensity (interview in the magazine star, 36/2005,S. 28).

names of hurricanes

original received only special Hurricans a name, about to “new England Hurricane”. 1950 began the Meteoroligists with the designation of the hurricanes. In that year as well as in the subsequent year first names were the used, thoseto the international phonetic alphabet at that time corresponded - thus Able, to Baker, Charlie, etc. English woman names were introduced in the year 1953. Starting from 1960 fixed lists of names with 21 names each were used before. The number of 21 fixed after the season 1933, thoseuntil 2005 the most active was and 21 registered tropical eddy towers had. The amount of was exceeded only 2005. In the year 1979 one used for the first time alternating male and female names, in addition one supplemented the English around French and Spanish names.There are at present six firm, lists of names fixed of the World Meteorological Organization, which are always periodically used. Thus the list of the yearly 2005 is again used in the year 2011.

It can however also happen that names completely of the listdisappear: If a hurricane caused particularly bad damage, the WMO can decide that its name is not any longer reused. Thus for example the name is „to Ivan “from the year 2004 together with three other name in the list for2010 no more - instead now the name is „Igor “registered. It is probable that from the list of names of the very active season 2005, which is reused 2011 for the first time more than four names are painted at one time.

During the first stormin each case each yearly in the Atlantic a name gets, which begins with a A, in the central Pacific (beginning with 140° west) the next name of the list is assigned, independently of year or letter.

Example:The hurricane forwards „Katrina “carried thatName „Jose “. After „Katrina “„Lee “followed and „Maria “. Since the first hurricane of each yearly with „A begins “, one can recognize easily, it already gave how many storms: „Katrina “was the 11. Storm of the yearly 2005, „Maria “of the 13.

Atlantic names

current. No. 2006 2007 2008 2009 2010 2011
1 Alberto Andrea Arthur Ana Alex Arlene
2 Beryl Barry Bertha Bill Bonnie Bret
3 Chris Chantal Cristobal Claudette Colin Cindy
4 Debby Dean Dolly Danny Danielle Don
5 Ernesto Erin Edouard Erika Earl Emily
6 Florence Felix Fay Fred Fiona Franklin
7 Gordon Gabrielle Gustav Grace gas clay/tone Gert
8 Helene Humberto Hanna Henri Hermine Harvey
9 Isaac Ingrid Iko IDA Igor Irene
10 Joyce Jerry Josephine Joaquin Julia Jose
11 Kirk Karen Kyle Kate Karl Katia
12 Lee Leslie Lorenzo lily Larry Lisa
13 Michael Melissa Marco Mindy Matthew Maria
14 Nadine Noel Nana Nicolas of NIC oils Nate
15 OSCAR Olga Omar Odette Otto Ophelia
16 Patty Pablo Paloma Peter Paula Philippe
17 Rafael Rebekah Rene rose smelling pool of broadcasting corporations Rina
18 Sandy Sebastien Sally SAM Shary Sean
19 Tony Tanya teddy Teresa Toma Tammy
20 Valerie Van Vicky Victor Virginie Vince
21 William Wendy Wilfred Wanda walter Whitney

should these will not be sufficient „name supply “in one year the following tropical storms after the Greek alphabet designated. This happened for the first time in the season 2005, as the 22. Tropical storm of the season alpha, the 23. Beta, the 24. Gamma,the 25.Delta and the 26. Epsilon were called. That only one month after the official season tropical storm number 27 arisen was called therefore Zeta, a further was gotten the name Eta. One should after the Greek alphabet designatedStorms so heavy damage cause that the name is painted by the list, then this letter in each following season, in which Greek letters to be necessary, one would jump over.

east Pacific name

current. No. 2005 2006 2007 2008 2009 2010
1 Adrian Aletta Alvin Alma Andres Agatha
2 Beatriz Bud Barbara Boris Blanca blow
3 Calvin Carlotta Cosme Cristina Carlo Celia
4 Dora Daniel Dalila Douglas Dolores Darby
5 Eugene Emilia Erick Elida Enrique Estelle
6 Fernanda Fabio Flossie Fausto Felicia franc
7 Greg Gilma Gil Genevieve Guillermo Georgette
8 Hilary Hector Henriette Hernan Hilda Howard
9 Irwin Ileana Ivo Iselle Ignacio Isis
10 Jova John Juliette Julio Jimena Javier
11 Kenneth Kristy Kiko Karina Kevin Kay
12 Lidia Lane Lorena Lowell Linda Lester
13 max of Miriam Manuel Marie Marty larva LINE
14 Norma Norman Narda Norbert Nora Newton
15 Otis Olivia Octave Odile Olaf Orlene
16 Pilar Paul Priscilla Polo Patricia Paine
17 Ramon pink Raymond Rachel Rick Roslyn
18 Selma Sergio Sonia Simon Sandra Seymour
19 Todd tare Tico Trudy Terry Tina
20 Veronica Vicente Velma Vance Vivian Virgil
21 Wiley Willa do not whale-read Vienna ever Waldo Winifred
22 Xina Xavier Xina Xavier Xina Xavier
23 York Yolanda York Yolanda York Yolanda
24 Zelda Zeke Zelda Zeke Zelda Zeke

further regions

see: Worldwide Tropical Cyclone Names

considerable hurricanes


  • Matthew Mulcahy, Hurricanes and society into the British Greater Caribbean, 1624 -1783, Baltimore: John Hopkins University press 2006, 257 S., ISBN 0-8018-8223-0

Web on the left of

Wiktionary: Hurricane - word origin, synonyms and translations
Commons: Atlantic hurricanes - pictures, videos and/or audio files
Commons: Pacific hurricane - pictures, videos and/or audio files

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