Natural Disasters

Cyclone Mocha is now the second-most intense May cyclone in Bay of Bengal

Mocha may intensify into a super cyclone before landfall  

By Himanshu Nitnaware
Published: Saturday 13 May 2023

Photo: @Indiametdept / TwitterCyclone Mocha on May 13, 2023, became the second-most intense cyclone to develop in the Bay of Bengal in the month since 1982, a scientist told Down To Earth (DTE).

Vineet Kumar Singh, researcher, Typhoon Research Center, Jeju National University, South Korea said Mocha intensified from category 1 (120 kilometres per hour) to category 4 (212 kmph) in 24 hours.

“This is tied with the second most rapid intensification by a pre-monsoon season cyclone in the Bay of Bengal since 2000,” he said.

Mocha’s windspeed currently is 130 knots or 250 kilometres per hour according to United States Department of Defense agency Joint Typhoon Warning Center.

So far, the top three most intense cyclones in May in the Bay have been: 

  1. Amphan, May 2020: 265 kmph
  2. May 1990 cyclone (Andhra Pradesh): 231 kmph
  3. May 1997 (Bangladesh) and Mocha: 212 kmph

On May 13, Mocha intensified into an Extreme Severe Cyclonic Storm category and may evolve into the ultimate category of ‘super cyclone’ just before landfall.

It had formed over the southeast Bay of Bengal on May 11 and is expected to make landfall on May 14 between Cox’s Bazar in Bangladesh and Kyaukpyu in Myanmar.

Raghu Murtugudde, a climate scientist at the University of Maryland and Indian Institute of Technology, Bombay, told DTE that the cyclone may reach the category just before hitting land. “The reason is because Mocha is moving slowly and the Bay of Bengal is warm,” he said.

Murtugudde said the weather system did not go as far west as predicted earlier. So, it is already heading east towards Myanmar.

Anupam Kashyapi, head of India Meteorological Department (IMD)’s weather forecasting department, Pune, said, “It was not expected that the cyclone would reach the Extremely Severe Cyclonic Storm category. But now it may just reach the super cyclone category if the intensification occurs.”

Roxy Mathew Koll from the Indian Institute of Tropical Meteorology (IITM), Pune, told DTE that Mocha underwent continuous rapid intensification as it intensified from 65 kmph to 120 kmph between May 11 and 12. It further intensified from 120 kmph to 213 kmph between May 12 and 13.

Koll explained that if the wind speed of a cyclone increases by 55 kmph in 24 hours, it is termed as rapid intensification. “In recent years, we see more of these cases wherein cyclones are intensifying quite rapidly due to warm ocean conditions,” he tweeted.

According to private forecaster Skymet weather, the tropical cyclonic storm had developed an eye on May 12 which indicates very strong winds circulating around the centre.

It stated, “Ocean heat has dominated and the warm sea surface has played a major role in its intensification. Environmental conditions are only marginally favourable for any further development.”

Skymet weather predicts the cyclone to weaken slightly before reaching the land due to “intrusion of dry air, increased wind shear and rugged terrain”.

The extreme weather system is expected to weaken to a Very Severe Cyclonic Storm with a wind speed of 160 kmph and gusting to 180 kmph. “The storm will weaken rapidly after hitting the coastline,” the statement from Skymet weather said.

However, the intensification of cyclone is likely to cause increased devastation in the Northeast than expected earlier.

The IMD statement predicts that heavy-to-very-heavy rains are likely to occur in Northeast India. Kashyapi said Upper Assam, Arunachal Pradesh, Nagaland, Mizoram and other areas are likely to face worst impacts. “The areas may also experience temporary flooding,” he said.

Debasish Jena, agrometeorology scientist, district agromet unit, Cuttack, said, “IMD expects minor damage to loose and unsecured structures. There may be some breaches in kutcha roads due to heavy rains with a possibility of landslide in vulnerable areas.”

The IMD also estimates uprooting of small trees, breaking of tree branches and damage to trees of banana, drum stick, papaya and others apart from loss of standing crops.

Jena said the advisory suggests to immediately harvest mature fruit and crops, protect fruit nurseries and vegetable plantations, avoid spraying of fertilisers and pesticides and keeping safe cattle and livestock in sheds.

Meanwhile, Murtugudde added that a second cyclone had spun up but went off west and stayed close to the equator. “Southwesterly winds are strong. So we just have to watch out to see whether any cyclones will be born in the Arabian Sea or the Bay before the monsoon onset happens,” he said.

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