Two more districts in Chumphon and Surat Thani were declared disaster zones yesterday, while the Meteorological Department forecast that violent waves in the Gulf of Thailand would continue until year-end.

The Disaster Prevention and Mitigation Department put Chumphon's Pathiu district and Surat Thani's Chaiya district on its disaster-zone list after they were hit by powerful waves and heavy downpours.

Four houses and two shops in Pathiu were swept away while in Chaiya the waves eroded seven kilometres of Sai Kaew Beach, and 30 temporary shelters used by small fishermen were washed away. Several fishing boats were reported as having sunk in the heavy surf.

Vijit Chantrapan, head of the Songkhla provincial Disaster Prevention and Mitigation Office, told residents of several sub-districts in Ranot to prepare for evacuation. Sandbags were piled along the beach to fend off the waves.

Provinces on the Gulf of Thailand from Surat Thani to Narathiwat have been pounded by waves up to four metres high since Thursday. There have been no reports of fatalities. The Navy has laid on patrol ships, rescue teams and helicopter patrols along the coast.

Suparuek Tansrirattanawong, head of the Meteorological Department, said Prachuap Khiri Khan, Chumphon, Surat Thani, Nakhon Si Thammarat, Songkhla and Phatthalung and islands in the gulf including tourist destinations Samui, Pha-ngan and Tao would face bigger waves from December 27-30.

Meanwhile, villagers in the upper North were warned to brace for a cold snap. The Meteorological Department yesterday said temperatures could drop to minus 4 Celsius on mountain tops and 7-8 degrees in urban areas of Mae Hong Son, Chiang Mai, Chiang Rai, Lampang, Nan and Phrae.