KALLAKKADAL (Syllabus GS Paper 3 – Disaster Management)

Context: Recently, numerous coastal areas in Kerala witnessed flooding as high sea waves, commonly referred to as swell waves, inundated hundreds of homes.

Kallakkadal

• About: It refers to coastal flooding caused by swell waves on the southwest coast of India during the pre-monsoon season, as described in a 2016 paper published in the AGU journal.
• Origin and Meaning: The term "Kallakkadal" originates from Malayalam, combining "Kallan" meaning thief and "Kadal" meaning sea, representing the ocean's intrusive nature during flooding events.
• Recognition: Local fishermen coined the term "Kallakkadal" to describe this phenomenon, which was officially recognized by UNESCO in 2012.

Kallakkadal different from tsunami: Kallakkadal is often confused with a tsunami but differs fundamentally.

• A tsunami is a series of massive waves caused by underwater disturbances like earthquakes, whereas Kallakkadal is a phenomenon of swell surges impacting coastal areas.
• Kallakkadal gained attention following the devastating 2004 tsunami, which claimed over 10,000 lives. However, the two phenomena are distinct in their causes and effects.

Causes of Kallakkadal

• Origin of Waves: Kallakkadal is caused by waves formed by an ocean swell, known as swell surge, which originate from distant storms like hurricanes or long periods of fierce gale winds.
• Energy Transfer: During storms, significant energy transfer occurs from the air into the water, leading to the formation of high waves that can travel thousands of kilometers from the storm center until they reach the shore.
• Southern Indian Ocean Winds: Typically, Kallakkadal results from strong winds in the southern part of the Indian Ocean, generating an ocean swell that travels northward to reach the coast within two or three days.
• Absence of Local Wind Activity: Kallakkadal often occurs without precursors or local wind activity, making it challenging for coastal populations to receive advance warnings.
• Early Warning Systems: Initiatives like the Swell Surge Forecast System, launched by the Indian National Centre for Ocean Information Services (INCOIS) in 2020, provide forecasts up to seven days in advance, aiding in early warning efforts for Kallakkadal.