Mumbai, May 17: Even as cyclonic storms affect the entire coast of India, the eastern coast is significantly more prone to cyclones as compared to the western coast. However, trend seems to changing, with severe cyclones are hitting the western coast of India for the past four consecutive years and experts have attributed this to 'climate change'.
"India's coast is extremely vulnerable to cyclones and cyclones have not been uncommon in India as every year, low to moderate cyclonic storms hit the Indian shores. With a coastline of 7517 km, the country is exposed to nearly 10 per cent of the world's tropical cyclones. It can be said that among the cyclonic storms that are formed in the Bay of Bengal, over 55 to 58 per cent approach and cross the eastern coast, while only 20-25 per cent of the cyclones that develop over the Arabian Sea hitting and crossing the western coast. However, in the past four years we have seen four consecutive years between 2018-2021,"said an IMD official.
The Bay of Bengal witnesses cyclones both pre-monsoon as well as post-monsoon. But why is the eastern coast of the country so prone to cyclones? Surface sea temperatures and humidity are directly related to the formation of cyclones. Since the Bay of Bengal receives high average rainfall, the possibility of cyclone formation is also high.
"Generaly typhoons (a mature tropical cyclone) originating in west Pacific Ocean send a pulse of low pressure from westward towards Bay of Bengal. These make the conditions in the Bay of Bengal favourable for forming cyclonic storms/ cyclones. As the formation of these typhoons have been reducing, these sending lesser pulse of low pressure thus preventing formation of cyclones," Rajesh Kapadia, Mumbai-based independent weatherman and founder of a popular private weather blog 'Vagaries of Weather'.
While the cyclones forming in the Bay of Bengal have been known, the fact that Arabian Sea too is witnessing frequent cyclonic storms having strong intensities is something that shows effects of chimate change. "The formation of cyclonic storms in east coast - Bay of Bengal seems to have reduced at least for past couple of years. Meanwhile unusual heating of Arabian sea (to 31 to 32 degrees Celsius) is making weather conducive for formation of cyclones," Kapadia added.
The Cyclone Tauktae, that hit the western coast, making its way to Gujarat's coastline on Monday after wreaking havoc in Karnataka, Kerala, Goa and even in Maharashtra is the fourth cyclone in the consecutive years to have developed in the Arabian Sea. While the cyclones in the region usually are seen post-monsoon, however, this is also the fourth cyclone to form in the pre-monsoon period (May-June) and of high intensity.
According to IMD Cyclone E-atlas, for the first time in the last 40 years, four consecutive years (2018, 2019, 2020 and 2021) a pre-monsoon cyclone in the Arabian Sea.
Prior to this, Cyclone Mekanu formed in 2018 hit Oman, whereas other three cyclones hit India west coast including Cyclone Vayu struck Gujarat in 2019 and Cyclone Nisarga made landfall in Maharashtra last year (2020). This year too, the cyclone Tauktae is reaching Gujarat shoreline. "Since last year, the cyclones forming in the Arabian Sea are being termed in the very severe cyclone category," said an IMD official adding that with a low-pressure system, there are multiple stages of intensification in order for a cyclone to form which is happening in case of Tauktae.
"In the case of Cyclone Tauktae in the Arabian Sea, the seawater has been quite warm even to the depth of 50 metres. Now is enough to supply an ample amount of energy to intensify the cyclonic storm," the official said.
Cyclones forming during the pre-monsoon period (May-June) and the post-monsoon period (October-November) have been known to produce severe intensity cyclones. " Since past three years, a trend of severe category cyclones forming in the Arabian Sea in the pre- monsoon season is seen. While cyclones hitting eastern coast consecutive years was common, now severe cyclonic storms forming in Arabian sea to hitting/crossing the western coast can be definitely attributed to climate change." VP Meteorology And Climate Change - Skymet Weather Services Pvt Ltd.
Cyclone Tauktae Facts
(Source - IMD Cyclone E-Atlas, Vagaries of Weather)
- First time after 1976 and only the second time since 1900, a cyclone in May hit Gujarat coast with wind speed greater than 35 knots.
- This is the third cyclone in last four years in the Arabian sea in pre-monsoon season that has attained 100 knots windspeed.
- This is the most severe intensification by a cyclone in the month of May in the Arabian sea since 1999.
- Cyclone Tauktae intensified from category 1 (Minimal damage capacity) to category 4 (extreme damage capacity) cyclone in just 24 hours.