Nakhon Si Thammarat is being deluged from runoff from the Khiriwong mountain range following two days of steady rain.
Flooding also hit the adjacent provinces of Phatthalung and Surat Thani, according to local officials.
The runoff, which lasted eight hours on Thursday, flowed quickly past Khiriwong village in Lan Saka District. It raised the level of a canal to reach the deck of a suspension bridge in Thaha village of Khiriwong sub-district. The run-off would reach Muang district of Nakhon Si Thammarat in 7-8 hours, local officials warned.
Meanwhile, floodwater was about 1.5 meters deep in Bang Yot village of Phra Saeng District in Surat Thani province. In Ipan Subdistrict, most houses that stand near the Ipan Canal were facing higher floodwater.
Persistent rain caused the level of the canal to rise and overflow into about 60 houses. Local Red Cross staff were helping victims there.