KALLAKKADAL
- Kallakkadal refers to coastal flooding occurring before the monsoon season in April-May along the southwest coast of India due to swell waves, as outlined in a 2016 paper titled "Teleconnection between the North Indian Ocean high swell events and meteorological conditions over the Southern Indian Ocean," published in the AGU journal.
- The research, conducted by P G Remya, S Vishnu, B Praveen Kumar, T M Balakrishnan Nair, and B Rohith of the Indian National Centre for Ocean Information Services in Hyderabad, explores this phenomenon.
- The term Kallakkadal, coined by local fishermen, originates from a combination of two Malayalam words, Kallan and Kadal, meaning thief and sea, respectively. According to the study, the amalgamation signifies the ocean's deceptive arrival. UNESCO formally recognized this term in 2012
- Kallakkadal occurs due to the presence of waves known as ocean swells, hence its association with the term "swell surge."
- Unlike local winds, these ocean swells are generated by distant weather phenomena such as hurricanes or prolonged periods of intense gale-force winds.
- During these weather events, significant energy is transferred from the atmosphere to the ocean, resulting in the formation of exceptionally tall waves.
- These waves can traverse vast distances, spanning thousands of kilometers from the center of the storm until they reach the coastline.
- Typically, Kallakkadal is a result of powerful winds in the southern reaches of the Indian Ocean, where ocean swells originate. These waves then travel northward, reaching the coast within a span of two to three days.
- In the most recent occurrence, a low-pressure system moved over the region around March 25, originating from the South Atlantic Ocean and located approximately 10,000 kilometres away from the Indian coast.
- The presence of this pressure system led to the development of strong winds, which in turn facilitated the formation of swell waves reaching heights of up to 11 meters
- Kallakkadal occurs without precursors or any kind of local wind activity and as a result, it has been very difficult for the coastal population to get an advance warning.
- However, early warning systems like the Swell Surge Forecast System —launched by the Indian National Centre for Ocean Information Services (INCOIS) in 2020 — gives forewarning seven days in advance
Why is Kallakkadal different from tsunami?Kallakkadal came under the spotlight after the 2004 tsunami that killed more than 10,000 people. However, Kallakkadal is often mistaken to be a tsunami, which is a series of enormous waves created by an underwater disturbance usually associated with earthquakes occurring below or near the ocean. |
- Kallakkadal, or coastal flooding caused by swell waves, is not unique to the southwest coast of India. Similar phenomena occur in various coastal regions around the world.
- For instance, in the Pacific Ocean, countries like Japan and Australia experience coastal flooding due to swell waves generated by distant storms or intense weather systems. Along the west coast of the United States, from California to Washington, swell waves originating from the North Pacific can lead to coastal inundation during certain times of the year.
- In the Atlantic Ocean, coastal areas of Europe, Africa, and the Americas can also be affected by swell waves, particularly during periods of heightened storm activity such as hurricanes or powerful extratropical cyclones.
- Overall, the occurrence of Kallakkadal-like events is not restricted to the Indian Ocean but can be observed in many coastal regions worldwide where the conditions for swell wave generation are met
The aftermath of Kallakkadal, or coastal flooding caused by swell waves, can be significant and wide-ranging.
Some of the aftereffects include:
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Property Damage: Coastal flooding often results in damage to buildings, infrastructure, and property located in low-lying coastal areas. Homes, businesses, roads, and agricultural land can be inundated by floodwaters, leading to structural damage and economic losses.
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Displacement of People: Residents living in coastal communities may be forced to evacuate their homes temporarily or permanently due to the flooding. Displacement can result in the loss of livelihoods, disruption of communities, and psychological distress among affected individuals and families.
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Impact on Ecosystems: Coastal flooding can have adverse effects on local ecosystems, including damage to habitats such as mangroves, wetlands, and coral reefs. The influx of saltwater into freshwater ecosystems can disrupt the balance of aquatic life and threaten biodiversity.
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Saltwater Intrusion: Infiltration of saltwater into coastal aquifers and agricultural land can contaminate freshwater sources and affect crop yields. Saltwater intrusion can also degrade soil quality and impact agricultural productivity in coastal regions.
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Environmental Pollution: Floodwaters may carry pollutants such as sewage, chemicals, and debris, leading to environmental contamination and posing health risks to humans and wildlife. Cleanup efforts following coastal flooding events are essential to mitigate pollution and restore environmental quality.
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Economic Impacts: The economic consequences of Kallakkadal can be substantial, including losses to businesses, disruptions to transportation and trade, and increased insurance claims. Coastal regions reliant on tourism may experience declines in visitor numbers due to concerns about safety and infrastructure damage
