Tropical cyclones: what are they and how they form

We begin this article with the definition of tropical cyclone. A tropical cyclone is A storm that occurs In the oceans of the tropical regionsthat is, approximately among the tropics of cancer and capricorn.

Some of the characteristics of the tropical cyclones that we can highlight are:

• Its characteristic structure is that of a Circular storm And they present one Quick rotation.
• In its center there is a low atmospheric pressure system: less than the 950 hectopascales, which is known as “eye.”
• In that “eye” the Meteorological situation is peaceful: In general, no clouds occur and there is calm.
• He “eye” diameter oscillates Between 10 and 50 kilometers: Surrounding it, there is a wall towards which the clouds are moving spiral.
• He Diameter of a tropical cyclone It is usually Between 200 and 500 kilometers: While it can reach up to 1,000 kilometers. Even so, it is about three times less than the storms of middle latitudes.
• He wind blows in Wrong Way: that is, anti -Horary (to the left) in the northern hemisphere and in a script (right) in the southern hemisphere.
• They can go to Any address: While the most usual is west and also towards the pole.

Finally, we can say that tropical cyclones are also characterized by presenting strong winds, large rainfall, large waves and abundant thunderstorms.

The classification of tropical cyclones can be divided into different categories according to the characteristics. To start, depending on The speed that reach the maximum winds in a sustained way, we can find three types of tropical cyclones:

• Tropical depression: When the wind speed is less than 63 km/h.
• Tropical storm: When the wind speed exceeds 63 km/h.
• Hurricane: When the speed exceeds 120 km/h (500 km/h) have been exceeded. Do not hesitate to take a look at the next Ecology article about hurricanes: what they are, how they are formed and categories.

The area within the tropical cyclone in which the winds have the strength of Hurricane usually reach a radius of about 80 km. Externally to that area, intensity is decreasing. On the other hand, it should be clarified that hurricanes receive different names depending on the place where they occur (being in any case the same meteorological phenomenon), these names are:

• Typhoon: In the North Western Pacific. Discover what is the difference between hurricane and typhoon, below.
• Cyclone: In the Arabic Sea and in the Bengal Bay.
• Cyclone tropical severe: In the southeast of the Indian Ocean and the Southwest of the Pacific.
• Cyclone tropical: In the southwest of the Indian Ocean.
• Hurricane: In the North Atlantic, in the Caribbean Sea, Gulf of Mexico, Eastern North and Central Pacific Ocean.

Finally, we can classify hurricanes based on Saffir-Simpson scalewhich establishes 5 categories depending on the speed that the wind reaches in a sustained way:

• Category 1 hurricanes: The maximum sustained winds reach speeds between 120 and 153 km/h.
• Category 2 hurricanes: The maximum sustained winds reach speeds between 154 and 177 km/h.
• Category 3 hurricanes: The maximum sustained winds reach speeds between 178 and 209 km/h.
• Category 4 hurricanes: The maximum sustained winds reach speeds between 210 and 249 km/h.
• Category 5 hurricanes: The maximum sustained winds that exceed 249 km/h.

We continue this article explaining how tropical cyclones are formed. In order for a tropical cyclone to originate, several requirements are needed that give rise to a depression or low pressures system:

• The water of the ocean surface must be higher than about 26-27 ºC: To facilitate the contribution of heat and humidity, instability and convection.
• Conditions of Temperature, humidity and atmospheric pressure uniforms In an extensive region.
• It is necessary that there are air convergence on surface: That is, the air converges towards an area and concentrates.
• There must be Height air divergence: That is, the air moves away from a central area outside.
• They need latitudes above 5th: Since the Coriolis parameter becomes almost null near Ecuador.

In addition, the formation of a tropical cyclone consists of several stages, which we explain in the following section.

The formation of this meteorological phenomenon consists of 3 stages. We detail below which are the 3 phases of tropical cyclones.

Start of the tropical cyclone

First, the cyclone begins with a undulatory disturbance:

• The East windsalso called winds, They move: accompanied by low wave -shaped pressures.
• This disturbance is growing and reaches the phases of tropical depression and tropical storm: it should be remembered that these phases are based on wind speed.
• He wind is moderate: Rain and clouds do not present a very defined organization.

Then, the wind exceeds 120 km/h (passing to be considered a hurricane):

• A cloud system is formed that are organized in Spiral bands.
• There is a constant Humid heat and air contribution which translates into movement energy.

Tropical Cyclone Maturity

Already in the maturity phase, the following events take place:

• The cyclone grows rapidly and takes a circular form.
• Inside the vortex or center of the cyclone The storm’s eye is formed: A quiet area as we mentioned before.
• There is Great speed winds: Due to the immense pressure difference between the interior of the cyclone and the periphery.
• Surrounding the eye of the cyclone, storm clouds are formed Cumulonimbos: then nimbostrates, highestrats and cirrostrats are formed successively and towards the edges.

Tropical cyclone decline

Finally, the tropical cyclone enters the decline phase. Let’s see what happens:

• The formed cyclone can endure approximately a week.
• It moves in different addresses: West or northwest in the case of the northern hemisphere and in southeast direction in the southern hemisphere, with speeds that do not exceed 25 km/h.
• When They reach the continents, They disappear: Since the contribution of humid and warm air is interrupted.
• The same It happens when it moves towards A cold ocean: When it reaches a latitude of 20º or 30º degrees and transforms into a depression or storm typical of the average latitudes.

Do you ask what are the effects of tropical cyclones? There are several consequences that we can have, the most important are:

• Intense rainfall: The level of the rivers ascends and floods can be caused in plain areas.
• Storm tide and high waves: The sea penetrates coastal areas with waves of more than 6 meters, which also translates into floods.
• Strong winds: an extremely strong wind that can knock down trees, electric power posts, etc. They can even detach the roof and roof of the houses.

However, the impacts of a tropical cyclone not only depends on these factors, but also on the response that society gives to this natural disaster when preventing such impacts.

It is estimated that in the last 50 years tropical cyclones almost 800,000 people have removed their lives. They have also caused material damage, which have resulted in economic damage of almost 2 billion dollars from the United States.

We leave you the following post of ecology Verde so you know how to prevent natural disasters.

The World Meteorological Organization created a Tropical cyclones programbased on which several activities are carried out in the different meteorological centers specialized in tropical cyclones. Meteorologists are able to forecast or predict the evolution of tropical cyclones, specifically they can predict:

• What will be The trajectory or displacement.
• If you are going to have changes to intensity.
• What will be the place Where it will touch soil And at what time.
• That speed It will take at the time it touches land.

To predict all this about tropical cyclones threatening, they help themselves:

• Satellites
• Meteorological radars.
• Computers
• Numerical prediction models.
• Other leading technologies and new techniques.

With all the data obtained from the monitoring of tropical cyclones, they must be issued real -time notices so that society can be prepared before this phenomenon. However, the prediction of tropical cyclones is not always easy, since they can undergo sudden changes in their trajectory and intensity.

In the last 50 years, 3 of the 10 most nefarious disasters of the world were due to tropical cyclones. In addition, deaths caused by these 3 disastrous tropical cyclones reach 43% of all deaths of those 10 disasters together.

When tropical cyclones reach high intensity, they choose to give them a name for public security reasons, since when they are named, it is favored that communication is more effective in the face of any adverse episode of strong winds, intense rainfall, etc.

The 3 most destructive tropical cyclones in recent years were:

• Hurricane Katrina: It happened in 2005 in the United States and about 2,000 people died, becoming the most deadly cyclone in the United States of recent times. In material damage the figure amounted to 125,000 million dollars.
• Hurricane Harvey: It took place in 2017 in the United States and is considered the strongest hurricane of Texas. 107 people died and economic damage is estimated that they were the same as for Hurricane Katrina.
• Hurricane Maria: It happened in 2017 in Puerto Rico. This tropical cyclone took the lives of almost 5,000 people and had material damage calculated at 43,000 million dollars.

Other memorable tropical cyclones names, ordered from greater to lower intensity are:

• Irma.
• Sandy
• Andrew.
• IKE.
• Ivan.
• Charley.
• Rita.

If you want to read more articles similar to Tropical cyclones: what are they and how they formwe recommend that you enter our category of meteorological phenomena.