A central agency recently issued alerts to travellers visiting coastal areas of Kerala and Tamil Nadu against the "kallakkadal phenomenon" (meaning a "sea that comes suddenly like a thief") observed 15 January onwards. The phenomenon refers to the sudden swell of the seas that cause rough waves. The affected areas are likely to be washed over by waves of up to 0.5 to 1.0 metres, suggesting a possible threat of sea surge, according to the Indian National Centre for Ocean Information Services (INCOIS).
