Kerala And Tamil Nadu Coastal Threat: Exploring The Kallakkadal Phenomenon

High sea waves have been experienced by Kerala for the past month, leading to flooding of numerous houses along Kerala's coastline.

The districts of Alappuzha, Kollam, and Thiruvananthapuram in the south-western coastal state were the hardest hit by the waves as reported by The Indian Express on Sunday.

Relief camps have been set up by authorities to assist those affected by the flooding. The sudden change is attributed to swell waves, known as the swell surge or Kallakkadal in Malayalam.

Kerala, Tamil Nadu Coastlines on High Alert

The coastal areas of Kerala and Tamil Nadu have been placed on high alert due to the "Kallakkadal phenomenon," which involves a sudden swell of the seas leading to rough waves. This alert was issued by authorities until 11.30 pm on Monday, urging coastal residents and fishermen to take precautions, as reported by First Post.

The Indian National Centre for Ocean Information Services (INCOIS), responsible for weather warnings for fishermen, advised fishing vessels to anchor safely in harbours and ensure a safe distance between boats to prevent collisions.

Additionally, INCOIS recommended that people avoid trips to the beach and all sea-related activities during this period to ensure safety and prevent potential accidents. The alert was prompted by the heightened sea conditions affecting these coastal regions, particularly Kerala and Tamil Nadu, with a focus on safeguarding lives and property from the impact of rough waves.

What is Kallakkadal?

Kallakkadal is a coastal phenomenon that occurs along the southwest coast of India, particularly affecting the states of Kerala and Tamil Nadu during the pre-monsoon season, typically from April to May. This phenomenon is characterized by sudden and intense ocean swell waves that impact the coastline, leading to coastal flooding and damage, as reported by Hindustan Times.

The term "Kallakkadal" is derived from Malayalam, where "Kallan" means thief and "Kadal" means sea. When combined, "Kallakkadal" conveys the concept of the sea behaving like a thief, referring to the unexpected and stealthy nature of the ocean swell waves that strike the coast without any apparent warning or change in local wind patterns.

These swell waves associated with Kallakkadal are unique because they are not driven by local winds or storms. Instead, they originate from distant storms or weather systems in the Indian Ocean or beyond, travelling across vast distances before reaching the coastline of Kerala and Tamil Nadu.

The impact of Kallakkadal can be significant, leading to coastal flooding, erosion of beaches, and disruption of coastal activities. Fishermen and coastal communities are particularly vulnerable to these sudden oceanic surges, prompting authorities to issue warnings and advisories during the peak season, as reported by Hindustan Times.

In 2012, the term "Kallakkadal" was formally recognized by the United Nations Educational, Scientific, and Cultural Organization (UNESCO), highlighting its significance as a regional coastal phenomenon affecting the southwest coast of India.

What causes these waves?

• Swell surges are caused by strong winds in the southern Indian Ocean, according to INCOIS.
• These winds occur unexpectedly and without prior notice or warning.
• Ocean swells result from distant storms like hurricanes or prolonged periods of fierce gale winds, as reported by First Post.
• Massive amounts of energy are transferred from the air to the water during such storms.
• This energy formation leads to the creation of extremely high waves.
• Waves formed during storms can travel thousands of kilometres from the storm's centre before reaching the shore.
• INCOIS attributes the swell surge to strong winds in the southern part of the Indian Ocean, occurring suddenly without specific indications or warnings.