Between Cuddalore and Pamban, the cyclonic storm 'Gaja' is set to make landfall bringing heavy rainfall to Tamil Nadu with a wind speed gusting up to 100 kmph, the Met office said.
As per reports, over 25,000 people were evacuated in south Tamil Nadu coast. State government has declared that 30,500 rescue personnel are on standby.
The district collectors of Tiruvarur, Thanjavur, Pudukottai, Nagapattinam, Cuddalore and Ramanathapuram declared a holiday for schools and colleges on Thursday.
The Central Water Commission (CWC) has advised constant vigil over dams.
The CWC has advised action as per the Standard Operating Procedure as heavy rainfall in catchment areas could fill up the dams fast in less than 24 hours.
While reiterating caution to fishermen to not venture into the sea, the state government has said that a comprehensive list of do's and don'ts have been circulated to the people on cyclone eve.
The Met office has warned storm surge of about 1.0 metres likely to inundate low-lying areas of Nagapattinam, Thanjavur, Pudukkottai and Ramanathapuram districts of Tamil Nadu and Karaikal district of Puducherry at the time of landfall.
The IMD also cautioned about major damage to thatched huts. "Roof tops may blow off" and communication and power lines may be affected it said adding standing crops could also be hit besides water intrusion in low lying areas.
(With PTI inputs)