Five villages were flooded in Wiang sub-district in Chiang Khong district of Chiang Rai Monday night. They are Ban Thung Sai, Ban Pattana, Ban Thung Dook Plai Nam, Ban Sop Som and Ban Thung Na Noi. Residents said it was the worst flooding there in four decades.
Landslides hit two houses, in Ban Rom Fa Thong and Ban Huai Han, in Por sub-district of Wiang Kaen district, with flooding also in Mae Ngoen and Ban Saeo sub-districts of Chiang Saen district.
About 30 power poles were toppled on Thoeng-Khun Tan-Chiang Khong Road in Ban Mai Pattana of Chiang Khong district after the rain undermined their foundations.
In Nan province, runoff and landslides were reported in 11 villages of four sub-districts in Bo Klue district. About 25 houses and 240,000 square metres of farmland were damaged.
There were no reports of casualties.
Chatchai Promlert, director-general of the Department of Disaster Prevention and Mitigation, said on Tuesday that the southwest monsoon would bring heavy rain, storms and flooding and possible landslides in the East and the South from July 8 to 12.
He said weather warnings were out for the four eastern provinces of Chon Buri, Rayong, Chanthaburi and Trat and the 11 southern provinces of Chumphon, Surat Thani, Nakhon Si Thammarat, Ranong, Phangnga, Phuket, Krabi, Trang, Satun, Songkhla and Phatthalung.
Mr Chatchai said small boats, including tourist boats, should not go out to sea this week.
He also warned of possible heavy downpours, storms and landslides in eight northern provinces namely Lampang, Lamphun, Mae Hong Son, Chiang Mai, Chiang Rai, Phayao, Phrae and Nan from July 8 to 10.