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Experts told News18 that roads, tunnels, subways and underpasses are particularly vulnerable to flooding, which can trap people and cause major disruptions because poor planning means floodwaters have no room to recede. Is.
The recent floods in Tamil Nadu highlight how vulnerable cities are when urban planning does not take flood risks into account. (PTI)
Cyclone Fangal, which is making headlines at the moment, has attracted the attention of meteorologists for its rare trajectory and possible intensity in the Arabian Sea. Cyclone experts say that although it is “not a rare event, it is the third recurring event of this nature since 2018”.
While these cyclonic events are becoming more frequent due to rapid climate change, the increased cyclonic activity in the Arabian Sea is due to the extreme warming of the ocean as a result of CO2 build-up in the atmosphere by human-induced emissions.
According to experts, the other big issue that needs to be addressed on priority is urban flooding and it can affect lives and property more seriously as the years go by.
Is Fengle the first cyclone of its kind?
Dr S Prasanna Kumar, former acting director of CSIR-National Institute of Oceanography and an expert working on cyclones and their structures for more than two decades, says: “Although Cyclone Fangal is rare, it is not unprecedented. This is a case where a cyclone forms in the Bay of Bengal, crosses, and then regroups, re-energizes and becomes another cyclone.”
Read this also Cyclone Fangal: How the storm got its name and what it means
Dr Kumar explains how Cyclone Gulab in September 2021 and Cyclone Gaja in November 2018 both followed a similar path to Fengal and gained strength over the Arabian Sea due to conditions that made it possible for them to reactivate and become another cyclone. were favorable for gaining momentum. Along the western coast of India in the Arabian Sea. However, in the case of Gaza, when it entered the Arabian Sea, it did not receive the necessary support and heat to reactivate and collapse.
He elaborated that the narrow geography of peninsular India often allows cyclones to cross with residual energy. “When a cyclone forms in the southern Bay of Bengal, it usually moves west or north-west, hitting the Indian coast or even Sri Lanka. “After landfall, while the system weakens, it may re-emerge as a severe cyclone upon entering the warm waters of the Arabian Sea.”
Dr. Kumar also explained about the specific behavior of Cyclone Fengal. “Unlike most cyclones, which dissipate quickly after landfall, Fengal persisted for a long time, causing significant rainfall during landfall. “Such prolonged activity after a landslide is unusual,” he said.
They linked this persistence to changing climate patterns, particularly the “secondary warming” period that occurs in October but extends well into November. Accordingly, the post-monsoon cyclone period was during October-November but recently it is extending till December. “Normally, this secondary warming should subside by November, however, during both the primary warming period and this secondary warming phase in April-May, the atmosphere is now storing heat at unprecedented levels,” he explained.
Kumar also explained the role of the Lakshadweep Sea, part of the warm pool of the Arabian Sea, in intensifying cyclones. “This area is one of the hottest in the tropics, especially during April-May. If Cyclone Fengal passes through this region, it is almost certain to re-emerge as a strong system.”
Urban flooding: a growing risk amid cyclones
Urban flooding, especially during cyclones, is becoming a major concern which can soon turn into a disaster. Cyclones bring heavy rain and strong winds that can cause widespread damage, but the real danger is often the floods that follow for which we are simply unprepared.
Experts say if we don’t act now, the problem could spiral out of control, leaving cities unprepared for future storms.
Dr Kumar warned, “Such cyclones bring torrential rains for a short period of time which can lead to flash floods, which every government should pay attention to and have contingency plans in place to ensure that life And there should be no loss of property.”
Urban flooding is no longer rare. Poorly planned cities with dense construction leave no room for flood water to drain away. Roads, tunnels, subways and underpasses are particularly at risk of flooding, trapping people and causing major disruption. Due to increasing population in cities, it is becoming difficult to manage water when storms occur.
In cities across India, rapid development is leading to buildings being constructed on marshy or low-lying land – areas that are prone to flooding. During drought, these areas may seem harmless, but once heavy rains occur, the results can be devastating.
The recent floods in Tamil Nadu highlight how vulnerable cities are when urban planning does not take flood risks into account.
When torrential rains fall for a short period of time, it takes only a short time for cities to be submerged. This not only destroys property and causes loss of life but also brings daily life to a halt. Governments are in a difficult position because this is a predictable crisis, yet little is being done to prepare for it.
“To prevent the worst, we need to focus on urban flood planning. Governments should identify flood-prone areas, improve drainage systems and stop construction in vulnerable areas. We cannot consider heavy rains as just a monsoon issue – even in months like December, cyclonic rains can cause floods,” the expert explained.
the arabian sea is warming
Dr. Anand Kumar Das, senior scientist and cyclone forecaster expert at the Indian Meteorological Department (IMD), also talked about the special nature of Fengal.
“Cyclones generally move towards the west or north-west. However, Fengal turned eastwards before reaching the peninsula, a phenomenon we call a ‘recirculating cyclone’. While it is more common over central and northern Bay of Bengal, it is rare for cyclones over southwest Bay of Bengal,” he told News18.
They reported that the fungus benefited from environmental conditions, particularly sea surface temperatures of around 29 °C, which supported its survival and proliferation. “Unlike many systems that disintegrate when they move over cold seas. Fengal flourished because of its location and favorable environmental changes,” said Dr Das.
In recent years, the region in the Arabian Sea has been experiencing more cyclones than usual. The biggest reason for this seems to be the warming of the Arabian Sea.
It is now well established that the oceans are warming due to global warming, which is primarily due to increased CO₂ concentrations in the atmosphere due to human activities. This warming is not limited to the surface layers but is gradually spreading to the deep ocean levels. Dr. Kumar explains that the Indian Ocean is warming at a much faster rate than other oceans globally, with this heat particularly concentrated in its western region, including the Arabian Sea.
The Arabian Sea has been witnessing a sharp increase in cyclone activity with several dangerous trends in recent years. Cyclones are now an annual occurrence, and some years see multiple storms.
“In 2019 alone, there were five cyclones: Super Cyclone Kyarr, Extremely Severe Cyclones Maha and Vayu, Very Severe Cyclone Hikkah, and Cyclonic Storm Pawan. According to a recent research paper published by JGR-Oceans, there have also been occurrences of back-to-back cyclones like Chapala and Megh in October–November 2015.
“Cocurrent cyclones in the Arabian Sea and the Bay of Bengal are becoming more common, as was seen with Luban (Arabian Sea) and Titli (Bay of Bengal) in October 2018. According to the expert, the number of extremely severe cyclones with wind speed between 90 to 119 knots has also peaked.
“Before the mid-1990s, the ratio that was observed was 1:4, meaning that one out of every four cyclones in the Bay of Bengal would make landfall in the Arabian Sea. Recently, it has become 2:1, which means more cyclones are occurring in the Arabian Sea than before,” Dr Kumar said.
In the early 90s, only two such cyclones were recorded, but by 2022 this has increased to nine.
Both cyclone experts pointed to wider implications of Cyclone Fangal’s behaviour. Dr Kumar observed a clear change in the cyclone pattern, with activity extending into December – a period previously considered unusual for cyclones in the Arabian Sea.
“Traditionally, cyclone season was limited to April-May and October-November. Now, we are seeing cyclones forming in June and December. This is a direct result of the increasing heat retention of the Arabian Sea,” said Dr Kumar.
Dr. Das said that the warming of the Arabian Sea is a result of the reduction in cooling period. “During the summer monsoon, strong winds and upwelling processes help cool the Arabian Sea. However, due to weak winds and low upwelling off the coasts of Somalia and India, the ocean is retaining more heat, which directly affects the intensity of the cyclone.”
IMD experts say that while Fengal appears to have weakened into a depression, it may re-emerge as a powerful system over the Arabian Sea. “We are monitoring its progress closely. “Chances of cyclogenesis are low, but conditions over the Arabian Sea remain favorable for re-intensification,” Dr Das said.
