High tides on the Chao Phraya River could flood low-lying riverside areas of Bangkok and six nearby provinces from 9 to 17 November, Thailand's disaster authorities have warned. The riskiest time each day is from the morning to around midday, when the tide peaks.

The warning follows announcement No. 15/2569 from the Hydrographic Department of the Royal Thai Navy, dated 5 November, which the Department of Disaster Prevention and Mitigation (DDPM) passed on the following day, Thai PBS reported.

Near the Royal Thai Navy headquarters in Bangkok, water is expected to reach about 1.70 to 2.00 metres between 07:30 and 13:30 from 9 to 16 November. The critical level there is 2.00 metres, so on the highest days the water will touch the edge of the defences. The DDPM warned that water may seep through the joints of flood walls, piers and drains even if the river does not overflow its banks.

At Phra Chulachomklao Fort in Samut Prakan, near the river mouth, water of about 1.80 to 1.90 metres is expected between 06:00 and 12:00 from 9 to 17 November.

Six provinces are on the DDPM's watch list alongside Bangkok: Pathum Thani, Nonthaburi, Nakhon Pathom, Samut Prakan, Samut Sakhon and Samut Songkhram. Residents are urged to watch riverside and canal areas, especially low-lying land, communities outside flood walls and places with no permanent barrier.

Anyone affected by flooding or blocked drains can call the DDPM on its 24-hour hotline 1784, or contact the service on LINE at @1784DDPM. In Bangkok, standing water and blocked drains can also be reported to the city hotline on 1555.