Cyclone Nisarga to hit coasts of Gujarat, Maharashtra today
It started as a warning on Sunday for mid-week heavy rains in Mumbai and by Monday, rapidly developed into a red alert for several coastal districts as the deep depression progressed over the Arabian Sea.
A deep depression over east-central Arabian Sea, which intensified into cyclone Nisarga on Tuesday noon is expected to make landfall as a severe cyclonic storm with a wind speed of 100 to 110 kmph gusting to 120 kmph near Alibag in Raigad district on June 3, the India Metereological Department (IMD) said on Tuesday. Located 94 km from Mumbai, Alibag is a popular seaside resort town for Mumbai’s elite and home to a large fisherfolk community.
It started as a warning on Sunday for mid-week heavy rains in Mumbai and by Monday, rapidly developed into a red alert for several coastal districts as the deep depression progressed over the Arabian Sea. As of Tuesday noon, cyclone Nisarga was 280 km west-southwest of Goa, 490 km south-southwest of Mumbai and 710 km south-southwest of Surat . The IMD said that the cyclone was likely to cross north Maharashtra and adjoining south Gujarat coast between Daman and Harihareshwar in Raigad on Wednesday afternoon.
The western coastline from Konkan’s Sindhudurg and Ratnagiri to Saurashtra’s Bhavnagar and other districts of Gujarat including Surat and Baruch have received wind warnings ranging from 55-65 kmph (gusting to 75kmph) and increasing to gusting speeds of 115-120kmph in four Maharashtra districts of Palghar, Mumbai, Thane and Raigad. Though a wide expanse of districts stands to be affected across coastal Maharashtra and Gujarat, higher wind speeds in the four districts mentioned above offer an indication of where the cyclone is likely to have maximum impact.
“The landfall location will be very close to Alibag but extensive damage can be expected in Mumbai also. For Mumbai, Thane and Raigad there can be storm surge of 1-2 metres and a warning for extremely heavy rainfall has been issued,” M Mohapatra, director general IMD, said.
Additional storm surge warnings — shoreward movement of water above astronomical tide height under the action of wind stress — have also been issued for Raigad, Thane, Greater Mumbai and Ratnagiri. Storm surges indicate the extent of inundation to expect. A storm surge of 0.5m to 1.3m over coastal Alibag may result in flooding up to 1.4km of low-lying area.
The city of Mumbai and its suburban satellite of Thane, already beleaguered by daily caseload of Covid-19 infections — the capital city breached the 40,000 mark at the start of the week — are in the cyclonic path, leading to concern over whether the city healthcare infrastructure would be able to cope. The IMD sounded a red alert as extremely heavy rains (over 20 cm) are expected in parts of Mumbai, Thane, Raigad, Sindhudurg, and Palghar among other districts.
Roxy Mathew Koll, senior scientist, Indian Institute of Tropical Meteorology (IITM) Pune, said that if landfall happened over Raigad, maximum rainfall should be expected over areas to its north, where Mumbai falls. “Not just the direct impact of winds but forecast indicates heavy rain up to 200mm while the Indian National Centre for Ocean Information Services has forecast storm surges with waves of 3-6 metres as the cyclone approaches landfall.If this happens during high tide on June 3 then flooding will be a major concern for a city that is already clogged.”
“The last severe cyclonic storm to hit close to Mumbai was in 1961. This storm is severe but with a wind speed of only 100 to 110 kmph. The important thing is to take all precautions possible, which state governments are trying. Inundation is possible so evacuation of vulnerable people is important,” said Mohapatra.
But experts warned that devastation can be extensive as today’s Mumbai is very different from the Bombay of 1960’s which has lost most of its floodplains and rivulets and is now counted as among the densest cities in the world. “Where are Mumbai’s floodplains now? Mithi river used to flow then, now it’s a nallah [drain]. Natural defenses like mangroves and rivers have been squeezed out of the city for expanding roads, buildings, and the airport. Hence, when heavy rains lash over a city like Mumbai which has lost its flood plains and defences, the flooding gets prolonged there too,”said Koll.
IMD officials said pre-monsoon cyclones like Nisarga were not a rare event, citing the example of very severe cyclone Vayu in June 2019, which was supposed to have made landfall over the Gujarat coastline, but ended up as a low pressure system. “We are observing the increase in pre-monsoon cyclones in Arabian Sea. While we should not draw a trend until observing such weather systems for at least a few years. However, we are assessing whether these systems are intensifying faster than before [which could be] due to numerous factors including rising ocean temperatures,” said Sunitha Devi, in-charge of cyclones at IMD.
“Some of the weakest cyclones at sea are being strengthened due to global warming and climate change impacts. This is no more a theory, and is being witnessed every monsoon in Arabian Sea now,” Anjal Prakash, author of an Intergovernmental Panel on Climate Change report, said.
The name, Nisarga proposed by Bangladesh, means ‘nature’. It is the 65th named cyclone in the north Indian Ocean and the second pre-monsoon cyclone to hit the Konkan coast since 1891. It comes in the wake of cyclone Amphan that devastated the lives of over a million people and left 86 dead when it made landfall as a very severe cyclonic storm on May 21 at the Sunderbans, in West Bengal.
Skymet, a private weather forecaster differed from the IMD’s prediction of the cyclonic path. “Our weather models are showing the landfall north of Mumbai with crucial period of extremely heavy rain and gale winds expected from Tuesday evening to Wednesday afternoon,” said Mahesh Palawat, vice president (meteorology and climate change).