The Kerala State Disaster Management Authority (KSDMA) set up 11 shelter camps in the state as cyclonic storm Maha in the Arabian Sea intensified into a severe cyclonic storm. It urged fishermen not to venture into the sea, putting several districts on yellow alerts.

Eight fishermen are already missing, according to Kerala chief minister’s office.

“Global warming is heating up Arabian Sea. So, we are going to see more cyclones and super cyclones in the coming years,” he added.

“Maha is not going to enter Kerala. It will pass by the Kerala coast. However, there would be heavy wind and rain. So, we have advised people to be cautious,” Sekhar Lukose Kuriakose, who heads the Kerala Disaster Management Authority, told Down To Earth.

“As the state will be hit by heavy winds, we have already opened 11 camps to shelter people as a precautionary measure,” Sekhar added.

The India Meteorological Department (IMD) stated that the storm was over Lakshadweep and adjoining southeast Arabian Sea, moving north-north westwards. It intensified into a severe cyclonic storm and lay centered over east-central Arabian Sea and adjoining Lakshadweep area, about 325 kilometre west-northwest of Kozhikode.

“It is ‘very likely’ to continue to move north-north westwards across north Lakshadweep Islands,” according to the update.

With the cyclone intensified, the IMD forecast wind at 100-110 kilometre per hour, gusting 120 kmph over east-central Arabian Sea from October 31 midnight.

“During the next 24 hours, gale wind speed reaching 80-90 kmph gusting to 100 kmph was likely to prevail over northern parts of Lakshadweep area and adjoining southeast Arabian Sea during the subsequent 24 hours and decrease gradually,” IMD updated.

Meanwhile, an update from the CM’s office at around 6 pm states that 11 shelter camps have been opened in five districts.

“There are 1,087 people from 365 families in these camps. Eighteen houses have been damaged completely in the rain and wind. 120 houses have suffered partial damage too,” the update read.

“Around 4 pm we received reports that two boats went north Kerala went missing,” an KSDM official said.

Lakshadweep was likely to receive extremely heavy rainfall and the IMD issued a “red message” for the island.

It technically referred to “take action”, meaning the state government machinery has to be on standby.

Weather expert Rajeevan Erikkulam pointed out that for the first time in the satellite era (since 1965) two cyclones were forming in the Arabian Sea around the same time, referring to Kyaar that is nearing the Oman coast.

237 million people in six Asian countries are at risk due to coastal flooding by 2050, a new study published in Nature Communications on October 29, 2019, has said.

The study is based on a new global coastal digital elevation model called ‘CoastalDEM’ prepared by non-profit ‘Climate Central’.

This is nearly four times more than the previous estimates of 54 million. The countries include China, India, Vietnam, Bangladesh, Indonesia and Thailand.

The study also notes that 300 million people would be under threat from coastal floods every year. That is nearly 73 per cent or three times more people being prone to risks than the earlier estimates of 79 million.

In India, six times more people are at risk from coastal flooding than the earlier estimates. Five million people in coastal regions were estimated to be under floods, but the new model projects 36 million people to be at risk.

The earlier estimates were made based on satellite data provided by NASA’s Shuttle Radar Topography Mission (SRTM). Satellite datasets were unable to provide the correct picture since they reported the elevation of treetops and rooftops, rather than the ground itself.

The new model, CoastalDEM, considered other aspects along with the vegetation cover and included population density and land slope among others.

The new model is thus much more accurate on estimating sea level rise and analysing coastal floods across the world, the scientists who created the model, said.

However, there is a catch. The new model is based on Representative Concentration Pathway 4.5, which assumes that humanity will moderately reduce warming emissions roughly in line with the 2015 Paris Agreement. But it is now known that the world is far from meeting the Paris Agreement’s goals.

Thus, the scientists warn that their new model’s projections might also be an underestimate on the extent of populations exposed to future flooding.

The study calls for vulnerable nations, especially in Asia, to strengthen their ability to cope-up with coastal disasters. It suggests that constructing levees and other defences or relocating to higher ground could lessen these threats.

The study also calls upon the world to reduce carbon dioxide emissions.

The Indian National Centre for Ocean Information Services (INCOIS), an autonomous body under the Union Ministry of Earth Sciences (MoES), in collaboration with the Airport Authority of India (AAI), launched two marine information dissemination products on October 9, 2019, to enhance the livelihood of fishermen and increase their security from extreme weather conditions.

INCOIS regularly provides information, advisories, ocean data, weather forecasts, potential fishing zones (PFZ) data to beneficiaries like fishermen, Indian Navy, marine industries, shipping etc.

But due to the limited range of mobile networks and VHFs, the erstwhile information system was not able to communicate disaster warnings to the fishermen if and when they moved away from the coast beyond 10-12 km.

The new system called GEMINI (GAGAN Enabled Mariner’s Instrument for Navigation and Information) has developed on this limitation by utilising GAGAN (GPS Aided Geo Augmented Navigation) satellite systems of the AAI to transmit PFZ and disaster warnings to the fishermen.

The data coverage of GEMINI covers the entire India Ocean full-time, which will help in information transmission to the fishermen far away from coastal areas.

Satheesh C Shenoi, the director of INCOIS, said this particular limitation of the marine information systems was acutely felt during the 2017 Ockhi cyclone wherein it was found that there was no way to communicate the cyclone warning to fishermen who had gone out for deep sea fishing before the onset of the cyclone.

Eighty-nine fishermen were killed and 143 had gone missing in Kerala alone, Down To Earth had reported.

GEMINI is a portable device which receives data from the GAGAN satellites and sends it to the user’s cellphone. The GEMINI app on the cellphone decodes the signals from GEMINI device and alerts the user on imminent threats like cyclones, high waves, strong winds along with PFZ and search and rescue mission.

“Due to its far and wide coverage across the Indian Ocean and its low cost, this product can also be sold to other countries” Balakrishnan Nair, a scientist with INCOIS, said in his presentation.

INCOIS also launched a new PFZ forecast model which would help the fishermen in forecasting potential fishing zones. Shenoi said that earlier, they were just able to provide potential fishing zone advisories using satellite data.

The fishermen used to get the data on that day’s fishing zones by the evening which made it nowcast instead of forecast. The new numerical model will use the same parameters used by the satellites, namely sea surface temperature data and the water’s chlorophyll content.

The new model will help provide advisories to the fishermen on PFZ, three days in advance. This system will also overcome the limitation of satellite-based data during overcast skies.

Nair claimed that these new products will benefit an estimated nine lakh fishermen in receiving better data service on marine weather events and PFZ.

Since the end user of this device are the fishermen, the Department of Fisheries has taken up the responsibility of funding the distribution of it through the state governments and National Fisheries Development Board, Shenoi said.

Pune, which had not seen floods in years, was hit twice by the disaster in 2019. First in early August and then in September; the latter was rather destructive. On September 25, parts of the metropolis were inundated after receiving 87.3 mm rainfall; at least 17 people were killed.

Most of the destruction and loss was experienced near the banks of Ambil Odha, a stream, and Bhairoba Nullah. There was more than 10 feet water in Sandeep Koshti’s house situated on the banks of the stream in Katraj area.

“I have never seen such flooding in the 15 years that I have lived here. This change happened when the width of the odha (stream) was reduced to about eight feet from more than 20 feet, and the depth was reduced to 3.5-4 feet from about 12 feet,” said Koshti.

“The odha can no longer carry the amount of water it used to. It has been killed!” he added while blaming rampant construction and destruction of mountains for this situation.

Changes in geography

The region resembles a saucer with hills on its edges. Ambil Odha originates in these hills, which are a part of the Western Ghats., in the southern part of Pune in Katraj area.

The stream flows from these hills towards the north, which is towards the centre of Pune. Many smaller streams join Ambil Odha before it meets the Mutha river. All these water bodies are part of the Krishna River Basin.

Balaji Baji Rao (aka Peshwa Nanasaheb, 1720-1761) reportedly built bunds on Ambil Odha after observing the natural depression in the landscape, recounted Shailaja Deshpande, one of the founders of non-profit Jeevitnadi.

During that time, Pune depended on the Ambil Odha as Mutha and Mula rivers were slightly far from the settlement. Bajirao created a lake system along the Ambil Odha, she added.

When the Katraj lake filled up, excess water went to the next lake in what is now the Rajiv Gandhi Zoological Park. The flow was then diverted to a beautiful lake near Sarasbaug to arrest run-offs coming from Katraj hills.

The Sarasbaug lake does not exist anymore. The size of Katraj lake is reduced and the edges are sharp and deep. It gets filled up with silt soon, she said.

Also, due to heavy mining and cutting of Katraj hills, flow channels of all first order and second order streams have either vanished, been diverted, or disturbed, said Deshpande.

So when there is heavy rainfall, water flows down like a sheet, resulting in flash floods, explained Deshpande. “Odha mhanje odhto to (Odha means the one that pulls), so it runs with force and speed,” she said.

The Katraj mountains have steep slopes, thin soil layer due to wind and water erosion, and dry deciduous vegetation. All this together increases run-offs, resulting in flash floods since historical times, she explained.

Shrikant Gabale, an expert in Geographic Information Systems and the director of Unity Geospatial, explained with maps what Koshti and Deshpande observed.

On comparing Survey of India maps, of the scale 1:25,000, with satellite images, he found that the built-up area had increased to 47 per cent in 2015 from 37 per cent in 1991. Streams existed till 1999, then they started disappearing. Water bodies reduced to 0.24 per cent in 2015 from 0.75 per cent in 1991.