Extensive damage caused by KallakkadalThe India Meteorological Department (IMD) often issue warnings about the phenomenon that affects the southern Indian coasts.
The likely cause behind the phenomenonAccording to IMD, strong winds in the southern Indian Ocean are to blame for the swell surges currently occurring on the southern coasts.
Such events caught more attention after the 2004 Indian Ocean tsunami because many people mistook Kallakkadal for tsunamis.
“They slowly moved towards the southern Indian Ocean (~35–55E; 60–50S) around April 28 and continued to create angry waves.
Caused by a low pressure that moved from the Atlantic Ocean into the Indian Ocean, these waves finally reached the South Indian coast this week,'' Kuriakose said.
On the afternoon of May 6, five doctors washed away while bathing at Lemur beach in Kanyakumari on the southernmost edge of the country. The doctors from Trichy in central Tamil Nadu were on vacation in Kanyakumari when tragedy struck.
Even though fishermen in the area heard the rumbling noise of the wave and rushed to help the 12-person team, they could only save seven; the five bodies were recovered from the turbulent water hours later.
In another incident, 42-year-old Premadas from Puthukadai, close to Kanyakumari, took his daughter Athisha (7) to Thengapattinam beach on the border with Kerala on May 5. They were relaxing on the beach when a sudden wave swept them away into the sea. Local fishermen managed to save Premadas but Athisha drowned; her body was found the next day.
They were caught unawares by the phenomenon known as ‘Kallakkadal’ or a sudden sea surge in the form of big waves that form and break on the nearest beach.
The Kanyakumari district administration said that at least eight people have died on local beaches in the last five days because of the Kallakadal phenomenon.
The word Kallakkadal means “a sea that comes suddenly like a thief.” The word is derived by combining two Malayalam words: "Kallan" (which means thief) and "Kadal" (which means sea).
Extensive damage caused by Kallakkadal
The India Meteorological Department (IMD) often issue warnings about the phenomenon that affects the southern Indian coasts.
The waves make it very hard for people to make a living along the southern coasts of both Kerala and Tamil Nadu. In fact, the beaches of Kanyakumari, Kovalam, Vizhinjam, Srivaikuntam, and Tiruchendur are currently all but closed to tourists because of the rough waves. Pilgrims have been warned not to go into the sea as part of the ritual bath in Thiruchendur and Kanyakumari. The waves also impact the livelihoods of fishermen in the area.
The rough waves make it impossible to get to the water directly and usually flood the shore areas, which are used to dry the nets used by fishermen. Many homes have been damaged in affected shore areas, and many have had to abandon their homes in fear.
The large waves that broke through the coastal road near Anchakadavu and filled the eastern side severely damaged the Poothura-Anchuthengu area around Thiruvananthapuram. The waves broke through the sea walls and damaged homes.
"Almost everywhere along the coasts of Thiruvananthapuram, Kollam, and Alapuzha districts, the waves have not yet gone away. The houses in the area are badly damaged because the coast has already been eroded in many places as a result of the construction of harbours, ports, and fish landing centres," said Valerian Isaac, leader of the Kerala Swathanthra Mathysathozhilali Union.
Surging waves also deposited a lot of sand on the homes of fishermen on the coastal road between Poothura and Anchuthengu, temporarily slowing down traffic. Most of the damage was in Punnapra, Arattupuzha, and Thrikkunnapuzha in Kerala's Alappuzha district. Many families have moved in with relatives outside coastal areas to avoid damage from the powerful waves.
The sea has also invaded into land in areas like Bekal, northern Kasaragod, and Kodungallur, central Kerala's Thrissur.
The likely cause behind the phenomenon
According to IMD, strong winds in the southern Indian Ocean are to blame for the swell surges currently occurring on the southern coasts. These winds come on quickly and without notice, which is where the name comes from.
During Kallakkadal events, the sea comes rushing onto land and floods large areas. Such events caught more attention after the 2004 Indian Ocean tsunami because many people mistook Kallakkadal for tsunamis.
"Tsunamis and Kallakkadal, or swell surges, are different kinds of waves caused by different things. Kallakkadal is smaller than a tsunami, but it often lasts longer and is strong enough to cause immense damages in smaller regions," said K. V. Thomas, former head of the Marine Sciences Division of the National Centre for Earth Science Studies.
"These flash floods happen quickly and without any changes in the winds or coastal conditions, which surprises the people who live there. Long-period swells that start in the Southern Ocean move north and hit the Indian beaches in three to five days, wreaking havoc on the area,'' said Thomas.
IMD has said that this phenomenon could recur in the coming days in coastal areas of Goa, Maharashtra, West Bengal, Odisha, Tamil Nadu, Kerala, Lakshwadeep, and the Andaman and Nicobar Islands. The agency has already suggested that "operational and recreational" activities be stopped at beaches, which are likely to be affected.
Fishermen and people who live near the coast have been warned to be careful of possible surging waves, which can look like seawater pouring in the nearshore/beach area, especially in low-lying areas.
Senior scientist and IMD group director T. Balakrishnan Nair said that high-period swells began on April 26 about 10,000 km from the Indian coast in the southern Atlantic Ocean.
“They slowly moved towards the southern Indian Ocean (~35–55E; 60–50S) around April 28 and continued to create angry waves. This will keep happening until at least the end of May,” they said.
Nair said that when these long-period swells meet with high tides, they will make it more likely that low-lying parts of coastal states will flood.
Ajith Shanghumukham, who heads a fishermen’s association in Thiruvananthapuram, said the situation hurts small-scale fish workers.
"Smaller fishing boats need to be anchored far apart so they don't hit and damage each other in the next few days. Swell waves can cause heavy flooding along India's east and west coasts even when the local winds don't show any signs of them. Often, the event destroys things along the coast,” said Sekhar Kuriakose, member secretary of the Kerala State Disaster Management Authority (KSDMA).
“For example, fishermen lose their boats and fishing gear when the coast suddenly floods. High swell waves of up to 11 metres create tension on the southern coasts and are a matter of concern. Caused by a low pressure that moved from the Atlantic Ocean into the Indian Ocean, these waves finally reached the South Indian coast this week,'' Kuriakose said.
Against the backdrop of these sea surges, the Kerala Tourism Department temporarily stopped operating seven floating bridges across the state's coastal destinations.
"Kallakkadal happens without any warning signs or local wind activity, making it hard for people living along the coast... However, early warning systems, like the Swell Surge Forecast System that the Indian National Centre for Ocean Information Services (INCOIS) launched in 2020, can inform people seven days in advance,'' according to Thomas.
