What do these whirl-winds have to do with us???




What actually is a hurricane?

A hurricane or –as it is called in Asia- a typhoon is a tropical whirl-wind which develops over the Atlantic or the eastern Pacific.

It is a swirling mass of clouds with a diameter of 200-1500 km that can exist for days or even for weeks and can cover long distances.

Hurricanes can be seperated in five groups:


Each hurricane gets a name. The name of the first hurricane of each season begins with the letter A, the second with the letter B etc. In 2005 we reached the letter V for the first time. With a wind speed of 63 km/h, a tropical wind system is considered as a storm and gets a name from meteorologists. Only from 118 km/h onwards is the storm called a hurricane. Hurricanes can reach a maximum wind speed of 400 km/h.

How does a hurricane develop?



A hurricane can only develop over the tropical sea when the temperature of the water is higher than 26°C (but there are exceptions: e.g. the hurricane near Madeira developed while the surface of the water only had a temperature of 23°C). 

Hurricanes can only be created between 3° and 5° north or south of the equator, because only in this area northwards in the northern hemisphere and southwards in the southern hemisphere can you find the characteristical revolution. The trigger therefore is the coriolis effect.


A hurricane consists of enormous thunderstorm cells (clusters) of the internal tropical convergence zone that comes over from western Africa with the trade wind currents over the Atlantic to the west and absorbs latent energy and dampness.

When the hurricane hits land, it quickly slows down, because the steam- and energy sources from the warm sea are no longer there and the friction with the soil accelerates the pressure balance of the air (the refracting effect of the coriolis effect is weakened). Often a hurricane ends up as a normal low pressure system  in our west wind zone with warm- and coldfronts, which are not found in the tropics.

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translated by Valeska, year twelve (THG)