Cyclone Remal made landfall between Sagar Island in West Bengal and Bangladesh’s Khepupara on the night of May 26. While Bengal’s coastal areas did take a knock, the cyclone left a bigger trail of devastation in the states of the North East.

At least 58 persons were killed across Mizoram, Manipur, Assam, Nagaland and Meghalaya as rain triggered by the cyclone led to floods, landslides, and widespread damage to homes.

The region is no stranger to cyclones in the Bay of Bengal bringing heavy rain, the extent of damage from Remal is without precedent, said climate scientists and meteorologists.

“This is the first time that a cyclone has had an impact of this magnitude in the region,” Sanjay O'Neill Shaw, a senior scientist at the regional meteorological centre of the India Meteorolgical Department told Scroll. “Most of the time, whenever a cyclone occurs in Bay of Bengal only some parts of Mizoram and Tripura are affected. But this time, the path of the cyclone changed affecting South Assam, Meghalaya and some parts of Manipur.”

“I have been here for the last 26 years,” said Gyanendra Dev Tripathi, chief executive officer, Assam State Disaster Management Authority. “I never heard of a cyclone entering Assam.”

A landslide in Mizoram killed over a dozen on May 18. Photo credit: Mizoram government

A powerful cyclone, a hot summer

According to climate scientists, cyclones that originate in the Bay of Bengal typically weaken by the time they reach the North East.

“Cyclones draw their strength from warm ocean water,” said climate scientist Rahul Mahanta, who teaches at Cotton University, Guwahati. “As they travel over land, friction weakens them. By the time they reach the northeastern states, they are usually weaker, bringing heavy rainfall and strong winds, instead of the storm surge and extreme winds associated with coastal landfall.”

So, what changed this time?

“Though it weakened over land, Remal originated as a powerful cyclone,” said Mahanta. “Even a weakened cyclone can carry significant moisture and wind.”

Moreover, Mizoram, Manipur and Assam sit “on the eastern fringes of the Bay of Bengal, making it susceptible to the outer bands of a cyclone's impact,” Mahanta said.

There is one more element that may have added to the cyclone’s fierce impact in the region – an unusually hot summer.

According to Raghu Murtugudde, professor of climate studies at the Indian Institute of Technology Bombay and emeritus professor at University of Maryland, Remal remained “fairly intact” after landfall because it had sucked up a lot of moisture from the warm Northern Bay of Bengal.

“But additionally, the very warm temperatures in the region since the beginning of March had left the atmosphere very humid. When the winds hit the hills in the North East [in these circumstances], that can lead to a lot of rain,” Murtugudde said.

People wade through a flooded street following heavy rains in Imphal on May 29. Credit: AFP

A warming planet

As scientists have predicted, the rapid warming of oceans due to climate change affects cyclonic behaviour. “Scientists studying the South Asian region believe warmer temperatures due to climate change are contributing to stronger and longer-lasting cyclones like Remal,” Mahanta said.

He pointed out that “the Bay of Bengal has seen a temperature rise, exceeding global averages, which provides energy for cyclones to form and intensify.” “There has been an increase in the intensity of cyclones in the North Bay of Bengal, precisely where Remal struck.”

Climate scientist Roxy Mathew Koll from Indian Institute of Tropical Meteorology, Pune, said the warming of the Indian Ocean is leading to cyclones with longer durations which can carry more rains. “In the case of Remal, in addition to global warming, it might have pulled in moisture from the monsoon clouds as well.”

In a social media post on May 19, Koll had pointed out that the sea surface temperatures in the Bay of Bengal were higher than usual.

What lies ahead

Experts pointed out that as cyclones increase in number and intensity, the North East is grossly unprepared, given its “inherent vulnerability” to erosion, landslides, floods, seismic activity and so on.

According to the National Climate Vulnerability Assessment report 2019-2020, Mizoram, Assam and Arunachal Pradesh are among states highly vulnerable to climate change.

Moreover, the region lacks adequate warning systems to cope with extreme events, said Imphal-based environmental activist Salam Rajesh.

The Manipur capital was submerged for days as Remal brought heavy rainfall, which led to two rivers overflowing. “We don’t have an early warning system and there was no quick response from the state government either.”

Mahanta, too, pointed out the lack of warning systems and administrative capacity to deal with extreme weather events. “The administration is more trained to act in floods, not cyclonic storms.”

Koll said regions that are prone to extreme rains, landslides and flash floods must first be identified. The governments must then make sure that these regions have the capacity to monitor and mitigate these impacts.

“We need to frame policies, build infrastructure and resilience considering the future weather impacts that we are going to encounter, not just the past impacts,” Koll said. “This is because all extreme weather events, whether it is heatwaves, cyclones, floods or droughts, are intensifying.”