Cyclone – Types, Formation, Cyclone UPSC Notes
By Balaji
Updated on: May 23rd, 2023
Cyclone is a meteorological effect in which a large wind system circulates at a center of low atmospheric pressure in an anti-clockwise direction in the northern hemisphere and a clockwise direction in the southern hemisphere. Cyclones can be marked by sighing winds moving towards the inverse side of a low-pressure zone. The Indian subcontinent has a coastline of 8041 kilometers. The majority of cyclones in India originate in the Bay of Bengal and move towards the East coast of India.
On average, the Indian subcontinent is hit by at least five to six Tropical Cyclones every year, out of which two or three could be severe. Based on the Indian Meteorological Department (IMD) analysis, more cyclones are formed in the Bay of Bengal than in the Arabian Sea, with an approximate ratio of 4:1. Cyclone is part of physical geography and many questions have been asked on this topic in UPSC previous year’s papers.
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What is a Cyclone?
Cyclones are strong winds or storms caused by the winds blowing around an area of low atmospheric pressure. In the area above the equator, which is the Northern hemisphere, it is called a Cyclone and rotates in an anticlockwise direction, whereas in the Southern hemisphere, it is called a hurricane or typhoon and rotates in a clockwise direction. The main characteristic of Cyclones is that they move in a spiraling movement in an inward direction.
Cyclone UPSC Notes
Tropical Cyclones form over warm water in the tropical region of the ocean where hot air is heated by the sun, creating areas of very low pressure. Due to this, the air rises at a very high speed and gets saturated with moisture that later forms thunderclouds.
| Type of disturbance | Associated maximum sustained wind |
| Cyclonic Storm | 34 to 47 Knots (62-88 kmph ) |
| Severe Cyclonic Storm | 48 to 63 Knots (89-117 kmph ) |
| Very Severe Cyclonic Storm | 64 to 90 Knots (118-167 kmph ) |
| Extremely Severe Cyclonic Storm | 91 to119 Knots (168-221 kmph |
| Super Cyclonic Storm | 120 Knots and above (≥222 kmph ) |
Cyclone Formation
Cyclogenesis has a major role to play in the formation and strengthening of Cyclones.
- Near the equator, tropical Cyclones form over warm ocean water.
- As a result, the humidified warm air near the ocean surface starts to rise upwards. This is followed by the formation of low pressure near the surface.
- The low-pressure areas get surrounded by the cooler air from nearby areas, and this cool air also becomes warm, and moist, and starts to rise upwards.
- This complete cycle keeps on continuing for a period of time.
- Later, when this warm moist air rises upwards, it cools down the water in the air, thereby forming clouds.
- During this whole process of spinning and growing, the wind and cloud interact with each other, and all of this results in a Cyclone.
- If the speed of winds touches the speed of 63mph, they are called tropical Cyclones, and if the wind reaches the speed of 119 mph, they are called hurricanes.
Types of Cyclones?
Depending upon the strength of the local winds, storm surges or tidal waves, and heavy rainfall, Cyclones in India are classified as tropical Cyclones, extratropical Cyclones, polar Cyclones, and mesoCyclones.
Tropical Cyclones
Tropical Cyclones occur in the region of the tropical ocean. There are two types of tropical Cyclones: hurricanes and typhoons. The Northeast Pacific and Atlantic regions experience hurricanes, whereas the Northwest Pacifica experiences typhoons.
Extratropical Cyclones
These Cyclones are formed in the middle latitudes, hence also called extratropical or mid-latitude Cyclones. The winds in the extratropical zone are relatively weaker. However, the temperature drops quite sharply.
Polar Cyclones
It occurs in the northern hemisphere and is also called an Arctic hurricane. In this, the heat transforms the water into the air and releases the latent heat, which further creates clouds. These types of Cyclones are difficult to predict as they take less than 24 hours to form.
MesoCyclone
MesoCyclones are the most severe and powerful types of Cyclones that produce thunderstorms. In the convective storm, the mesoCyclone appears as a vortex. This polar vortex rotates along the vertical axis. In the given hemisphere, both this airflow and the low-pressure system are pointing the same way. And this mesoCyclone comes into formation by rotating air inside the thunderstorm.
Naming of Cyclones
The nomenclature of the Cyclones is maintained by the World Meteorological Organisation. Earlier, the organization created a list that had names only of women, but later, after 1979, men’s names were also included in the list. The women’s and men’s names are used alternatively. There are a total of 6 lists in total and they are used in rotation, which means if the list has been used in 2022, then the same list will be used in 2028.
Cyclones in India
- India is surrounded by the largest water bodies on all three sides, and all the water bodies act as a hotspot for Cyclones.
- Some states, like Gujarat, Tamil Nadu, Kerala, Odisha, and West Bengal, are more prone to Cyclones.
- Since these Cyclones are accompanied by plentiful rainfall in India and high-speed winds, they become more deadly.
- Strom surges, strong winds, and various types of rainfall cause immense destruction to the surroundings.
Understanding AntiCyclones
As the title suggests, an anti-Cyclone is the opposite of a Cyclone. As opposed to a Cyclone’s inward spiraling action, antiCyclones flow in an outward motion, which is the opposite of that of Cyclones. Furthermore, the winds of an antiCyclone rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. Winds of antiCyclones are usually not as strong as those of cyclonic winds.
To implement a holistic approach to disaster management in India, the National Disaster Management Authority (NDMA) came into existence through the Disaster Management Act on December 23, 2005. It is headed by the Prime Minister of India and creates policies on disaster management as per the national plan.
Read: Difference Between Cyclone and Anticyclone
Cyclones UPSC
In the UPSC exam, questions related to cyclones, their causes, types, and their impact on society and the economy are commonly asked. Therefore, a good understanding of cyclones is important for aspirants, as it reflects the government’s efforts to mitigate the impact of these disasters and protect the lives and livelihoods of people. That’s why we have covered the Cyclones in detail formate which would help you to have an effective preparation for the upcoming Civil Services Exam. Candidates can also take the help of NCERT Books for UPSC to strengthen their basic foundation and also the side books of Geography books to gather more information on Cyclones.
Cyclones UPSC Prelims Sample Question
Question: Consider the following statements- 1)Cyclones are distinguished by a low-pressure center, 2)The northern hemisphere has anticlockwise wind flow while the Southern hemisphere has clockwise wind flow, 3) It’s a storm system with a heated Core. Choose the correct answer: A) 1 only B) 2 and 3 C) 1 and 2 D) All of the above
Answer– All of the above
Question: A low-pressure area in the atmosphere in which winds spiral inwards is _________? options– Cyclone, AntiCyclone, front, tsunami
Answer– AntiCyclone
