With “Amphan” devastating southern parts of West Bengal and Northern Parts of Odisha, let’s dig deep into the why Bay Of Bengal is Prone To Cyclones.
Every time a cyclonic storm generates an oceanic region of India there are 70 per cent chances that it will strike the Eastern parts of India and would have originated from the Bay of Bengal.
In 2019 the Severe Cyclonic storm “Fani” created havoc in the coastal parts Odisha, and in 2020 Amphan creating a mess in Digha and Sundarban areas in West Bengal.
Let’s look into the Scientific factor which makes Bay Of Bengal prone to cyclones.
Cyclones are formed due to intense spiral water rotating systems formed due to strong winds which develop over low-pressure areas over seawater. The ideal temperature for a cyclone to generate is around 25-27 degree celsius which helps to sustain moisture.
Cyclones do occur in the Arabian Sea also but in the Bay of Bengal sees 5 times more cyclonic appearances and 60 percents hit the east coast of India as compared to only 25 per cent in the Arabian sea because of the higher sea surface temperature as compared to the Arabian Sea.
Due to its Higher Sea Surface Temperature, it can trigger very Strong Cyclones. According to weather underground, it can trigger severe cyclones and 26 out of 35 deadliest cyclones have developed over here.
Also because of the lower hight of Eastern ghats as compared to the Western ghats, the mountains in the east coast of India are unable to block the stronger cyclonic winds which develop over the Bay, as stronger winds require more room to become stronger which makes Bay of Bengal so prone to Cyclones.
Due to the higher height of western ghats, these obstruct the flow of the cyclonic winds generating in western ghats.
Factors affecting from the South China Sea
Whenever there is cyclonic storm or activities developing in the South China Sea there would be a depression in the Bay of Bengal as the leftover moisture would be passing to the Bay.
One of the factors which make the Bay of Bengal so prone to cyclones is that it receives higher rainfall and freshwater from the Ganga and Brahmaputra basin which makes the surface water in the Bay getting refreshed regularly and making it impossible for dissipation of heat.
As the warm water on the sea surface is unable to mix the cool water which creates depression and making the Bay of Bengal prone to cyclones.
Contradictory in the west, the Arabian sea has much stronger winds and the lack of fresh water supply from rivers in the west makes the heat dissipation becomes easy.
Pre Monsoon and Post Monsoon
Bay witness Cyclonic activities in both before the monsoon and after the monsoon. However, the chances of Cyclones in Post monsoon period i.e the retreating period of monsoon are higher because of the absence of air movement from the mainland of India to the Bay which leads to cloud formation over there and making it cyclone friendly.
Pre-monsoon have less chance of cyclone formation as hot winds move from mainland of India to the bay obstructs the cloud formation but still, there are chances of Cyclonic activities as 2019 the Super cyclone “Fani” devastated the coastal regions of Odisha in pre-monsoon period with “Amphan” being the latest to the dictionary.
One more major factor making the Bay of Bengal prone to Cyclones is the Wind shear. There are 2 types of wind shear -Vertical, Horizontal.
Horizontal wind speed:- change in wind speed w.r.t to latitude
Vertical wind speed:-change in wind speed w.r.t to altitude
For a cyclone to develop a lower vertical wind shear is needed.
The Bay of Bengal serves this perfect with Relatively higher Sea Surface Temperature accompanied with Lower wind shear is able to hold the moisture for a longer time and the central area of the Cyclone remains warm.
With the above factors combined makes the cyclones developing in the Bay much deadlier and those developing in the Arabian Sea.
Some of the Major cyclone which developed in the Bay of Bengal in recent years:-
- Bhola in 1970 –the deadliest cyclone ever developed in the Bay of Bengal with total casualties over 500k and windspeed of 240kmph
- 1999 Odisha Super Cyclone:-with windspeed up to 260 mph and caused around 10,000 deaths
- 2019 “Fani”:-max wind speed of 250kmph which caused severe damage to architecture, puri, ganjam, paradeep district
- 2013 “Phailin”:- with wind speed up to 215 kmph
- 2014 “Hudhud”
- 2018 “Titli”
So whenever you are planning to go visit the eastern coastal parts of India try to visit in the months of December to April, the winds are calm and the weather remains less humid as compared to other seasons.
Also read out the article related to Tropical Cyclones in The Hindu
Also, have a look into the article related Northeast
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