Everything about Cyclones: Formation, Causes and Impact

Information collected by satellites suggests that cyclones generally form in low-pressure zones and over warm intertropical waters. These are gigantic and deadly storms that create havoc and severe damages to life and property.

According to the World Meteorological Organisation approximately 85 tropical storms develop over the warm tropical latitude oceans.

Read on to find everything about the types, causes, occurrence, impact, hazard zones and preventive measures of cyclones in this article.

In meteorological terms, a cyclone is a wind system that rotates inwards (counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere) around a strong low-pressure centre.

Generally, when winds rise above 118 kmph, it is known as a cyclone. These rotating winds forming over the Indian ocean and south of the Pacific Ocean are termed as cyclones. In other regions they are usually called by different names such as, typhoons, hurricanes etc.

To understand the severity of cyclones, one must learn in detail about its process of  formation and its categories.

Scroll down to the following section to understand the formation of a cyclone -

• Warm and moist air over the ocean rises upward due to less density,  leaving less air near the ocean surface,As a result, it starts to create a low-pressure zone.
• Due to the surrounding high-pressure areas, air flows into this low-pressure and eventually warms up, forming a cycle.
• With the constant heating rising of the warm air and evaporation process,  the entire cloud and wind system starts to spin and grow.
• With acquiring more speed, the eye of the cyclone starts to form in the centre. This central zone signifies the lowest air pressure area and is calm and clear. Further, the high-pressure air from above flows towards this region.

When the wind’s rotating speed reaches 63 kmph, it is called a tropical storm. However, when wind speed reaches 119 kmph, tropical cyclone formation takes place.

Now that you know the process of formation of a cyclone, let's take a look at the categories of a cyclone.

After knowing the answer to your question, "how are cyclones formed?" you might also like to know about why a cyclone occurs or what causes it.

Here are the factors responsible for cyclone formation -

• Warm temperature at sea surfaces.
• Coriolis force impacts the area that forms a low-pressure zone.
• Atmospheric instability.
• Increased humidity in the lower to middle levels of the troposphere.
• Low vertical wind shear.
• Pre-existing low-level disturbance or focus.

Now that you know how cyclones are formed and what causes them, let's look at the types of cyclones that have occurred in India over the years.

If you know how a cyclone is formed, you must know that it is often accompanied by strong winds, torrential rains and storm surge. These three elements causes impact to a great extent in the following ways -

• Strong winds cause damages to infrastructure, uproots trees, and lead to other catastrophes.
• Torrential rainfall leads to unprecedented floods and damages to houses and buildings.
• Due to storm surge, seawater levels rise, and the coastal areas are exposed to flooding.
• The rise in seawater level also erodes beaches and embankments.
• Severe cyclonic storms resulting in floods can damage vegetation and livestock.
• Due to the strong winds and conditions, the soil tends to become infertile.

In addition to this, cyclonic storms result in the loss of human, plant and animal lives and affect the country's economy.

Next up, let's look at the cyclone-prone zones in India.

As per the Indian Meteorological Department, 13 coastal states and Union Territories in India are prone to a cyclone. The eastern coast of India is more prone to cyclonic conditions than the western coast. However, because of the long coastline of India of 7516.6 km both the coasts of India experience cyclonic storms quite frequently.

Among both the coasts, some states are more vulnerable to cyclones than the others. The most vulnerable states in India that are majorly prone to cyclonic impact are as follows -

• West Bengal
• Andhra Pradesh
• Tamil Nadu
• Odisha
• Puducherry (UT)
• Gujarat

People residing in and around the above areas must equip themselves with certain preventive measures to carry out any damage control.

The National Disaster Management Authority (NDMA) advises individuals to take the following steps to stay safe during cyclones -

• It is necessary to stay indoors during a cyclonic storm and keep away from electrical mains.
• In extreme situations, one must prepare an emergency kit that is essential for survival.
• It is also vital to keep tabs on regular  weather forecast updates and rely on official warnings.
• In case your house is unsafe, it is advisable to shift before the onset of a cyclone.

Further, in collaboration with the NDMA, the Government carries out proper evacuation measures for fishermen and the coastal dwellers before the cyclone makes landfall.

With a detailed knowledge of how cyclones are formed and their causes, one can take sufficient precautions and avoid the harsh consequences.