Thiruvananthapuram | The Indian National Centre for Ocean Information Services on Saturday withdrew a 'red alert' issued for 'Kallakkadal' in the coastal areas of Kerala and the south Tamil Nadu coast and revised it to an 'orange alert'.

'Kallakkadal' is a phenomenon of sudden sea swells causing rough waves in coastal areas.

As part of the phenomenon, the low-lying areas of the Kerala coast are likely to experience rough sea and sea surge due to extremely strong waves of 0.5 meters to 1.5 meters till 11.30 pm on Sunday, the INCOIS said.

The low-lying coastal areas of south Tamil Nadu are also likely to experience a similar situation and high waves of 0.5 meters to 1.8 metres may cause sea surge there till tomorrow night, the agency warned.

INCOIS, the central agency that issues weather warnings for fishermen in the country, advised people to safely moor their fishing vessels in the harbour.

Authorities advised people to continue their caution and avoid trips to the beach and completely stay away from activities at sea.

The term 'Kallakkadal' literally means a sea that comes suddenly like a thief.

INCOIS has earlier said that the swells result from strong winds in the southern part of the Indian Ocean at certain times, and that they occur suddenly without any particular indications or warning which is why it is named 'Kallakkadal'.