Tropical cyclone


Tropical cyclones are considered one of the most dangerous natural hazards for people. Each year these cyclones are responsible for causing a great deal of considerable loss of life and doing immense damage to property and the environment . However, tropical cyclones are essential features of the Earth’s atmosphere , and to some extent they are also important, since they are responsible for transferring heat and energy between the equator and colder regions near the poles .


What is a tropical cyclone?

tropical cyclone is a phenomenon formed by high intensity rains and winds connected to each other by a pressure center that can cause enormous damage due to its force and violence.

  • Definition of tropical cyclone
  • features
  • Types of tropical cyclone
  • Tropical cyclone formation
  • Causes
  • Stages
  • Movement
  • Effects edit
  • What to do in case of a tropical cyclone
  • Examples

Definition of tropical cyclone

A tropical cyclone is a complex group of a series of elements that are released until reaching a point of maximum growth. The cyclone is born from the formation of a very low pressure center that is located on the sea ​​surface and that drags winds causing the air to condense and form steam around it. The center of the cyclone is known as the ” eye ” and is the warmest part of the cyclone. This area is where the winds circulate downward until they reach the surface . Rainy bands form around the eyewhich are spaces in which very heavy rains occur, which are important parts of the cyclone. These rains are formed from the vaporization of the air that occurred in the eye and then takes the form of precipitation .



The main characteristics of the tropical cyclone are the following:

  • It forms progressively on the surface of the sea .
  • It is formed by a combination of rain and wind
  • It has the ability to produce floods , destruction of buildings and houses.
  • They can generally be produced in the Caribbean Sea , Gulf of Mexico and in the Atlantic Ocean
  • They have a fairly warm central core .
  • It is seen as a giant whirlwind accompanied by wind, rain, and clouds.
  • It has bands of torrential rain in the shape of a spiral.
  • Its winds so usually grow in intensity conforms progresses.
  • Its formation depends on rainfall , sea temperature and the presence of convergence at the lowest levels.

Types of tropical cyclone

The types of tropical cyclones or their classification is as follows:

  • Tropical depression : it is a tropical cyclone that has maximum winds on its surface of 62 km / h. or less.
  • Tropical storm : it is a tropical cyclone that has a hot core and its maximum winds are between the range of 63-117 km / h.
  • Hurricanes : this is a tropical cyclone that also has a hot core in which the minimum wind is 118 km / h.

Tropical cyclone formation

Tropical cyclones form and also gain intensity when they are located over tropical or subtropical oceans in either of the two hemispheres , places in which the earth’s rotational force , known as Coriolis , is strong enough to initiate rotational motion around the low pressure center and where additionally, the surface water temperatures are 27 ° C or warmer. Generally, tropical cyclones develop in places where the vertical wind is weak since the strongest winds are generated at low levels.

They also may form in the instability of the south end of a cold front and sometimes form in areas of low pressure of cold core which are located in the atmosphere above


There are three causes or conditions necessary for the formation of a tropical cyclone that can even later become a hurricane , these are the following:

  • That there is a pre-existing disturbance or in other words a large area of cloudiness with rains, showers and thunderstorms.
  • That there is a warm temperature of the ocean waters: 26.6ºC or higher than this, up to a depth of at least 45 meters.
  • That the winds that are located in the upper atmosphere are weak and that they also do not change direction and speed through the height of the atmosphere.


The stages that a tropical cyclone has are four and they are the following:

  • Birth or tropical depression : the first thing that forms an atmospheric depression , characterized by the fact that the wind increases its maximum speed to 62 km / h or less, the clouds begin to organize and the pressure drops to about 1000 hpa.
  • Development or tropical storm : the tropical depression develops into a tropical storm , the increases between 63 and 117 km / h, the clouds are placed in a spiral shape and a small, circular eye is formed , reducing the pressure to less than 1000 hpa . In this phase it is named in the list formulated by the World Meteorological Organization.
  • Maturity or hurricane : the tropical storm intensifies becoming a hurricane , the wind reaches even 370 km / h , and the cloud area expands up to 500 and 900 km in diameter, causing intense rainfall . The eye of the hurricane, whose diameter varies between 24 and 40 km, is an area of ​​calm without clouds. The intensity is graduated by means of the Saffir-Simpson scale .
  • Dissipation or final phase : the whirlpool is maintained and nourished until it reaches colder waters or until it reaches land, where it quickly loses its energy and begins to dissolve .


The movement of tropical cyclones is of spiral rotation , but in addition to this, tropical cyclones move towards geographical regions far from their place of origin. The direction of movement is governed by the systems surrounding the tropical cyclone. Movement generally occurs in two directions, the first one general direction to the west or west to reach a point where decreases its speed or parked , then drastically change back to the direction of motion, changing its direction to the North , North- northeast . In June ,October and November , the movement is to the north , and in July , August and September , the trajectories extend from the coast of Africa to the West.

Effects edit

The effects of tropical cyclones can be quite powerful. The strong winds that cyclones have can damage houses, buildings, bridges and at the same time can turn parts of buildings into projectiles that fly at high speeds. The storm surge cyclonic produce an increase in the level of the sea causing flooding near the coast. Its torrential rains and electrical activity can cause large floods and the overflowing of rivers wreak havoc on the land. Sometimes tropical cyclones formtornadoes which can be deadly. The diseases , the cuts of energy and the difficulties of transport for help are normal situations observed in the passage of a tropical cyclone.

What to do in case of a tropical cyclone

In case of facing a tropical cyclone, there are some security measures that must be followed, among them we mention:

  • Remain calm and reassure your family members.
  • Maintain a battery – powered radio to stay informed.
  • Disconnect appliances and electrical power switches .
  • Close the gas and water stopcocks .
  • Stay away from doors and windows .
  • Do not use candles or candle holders and use battery-operated lamps.
  • Raise valuables to the higher parts and leave those that may fall on the ground.
  • Stay away from areas where floods can occur .
  • Seek shelter if necessary.
  • Do not leave the houses.


Some examples of tropical cyclones are:

  • Cyclone Bhola
  • Hurricane Mitch
  • Galveston Hurricane
  • Typhoon Tip
  • Hurricane Wilma
  • Hurricane Camille
  • Typhoon Nancy
  • Cyclone Catarina
  • Hurricane Katrina
  • Hurricane Harvey

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