Warning Issued for Multiple Provinces to Watch for Flash Floods and Flashy Floods from 11-13 Sep

The National Water Resources Office has issued a warning to monitor stagnant flooding, flash floods, flashy floods, and riverbank overflows from 11 to 13 September, listing the provinces at risk and urging preparations.

On 11 September 2026, the National Water Resources Office issued announcement No. 3/2569 (additional), concerning monitoring of stagnant flooding, flash floods, flashy floods, and riverbank overflows. This follows their previous announcement No. 3/2569 on 8 September 2026 on the same topics.

The National Water Resources Office has been monitoring weather forecasts and found a monsoon trough crossing the North, Central, Northeast, West, and South regions, entering a strong low-pressure area over the central South China Sea. This, combined with a strengthening southwest monsoon, is causing increased rainfall with heavy to very heavy rain in some areas, especially in the lower Northeast, Central, West, and South regions.

The Office has evaluated and analyzed water situations based on rainfall forecasts from the Meteorological Department, the Hydro-Informatic Institute (Public Organization), and flood and landslide risk forecasts from the Department of Water Resources and the Department of Mineral Resources. They identified risk areas requiring monitoring for flash floods, flashy floods, landslides, and stagnant flooding in urban areas from 11 to 13 September 2026 as follows.

Areas at risk of stagnant flooding, flash floods, flashy floods, and landslides.

• Northern Region. Mae Hong Son Province (Mueang Mae Hong Son District), Chiang Rai Province (Mae Lao, Mueang Chiang Rai, Pa Daet, Wiang Chai, Mae Sai, and Thoeng Districts), Sukhothai Province (Si Satchanalai District), Phetchabun Province (Si Thep, Wichian Buri, and Nam Nao Districts).
• Northeastern Region. Loei Province (Phu Kradueng, Tha Li, and Phu Luang Districts), Khon Kaen Province (Phu Pha Man, Nam Phong, Wiang Kao, and Si Chomphu Districts), Chaiyaphum Province (Thep Sathit, Mueang Chaiyaphum, and Bamnet Narong Districts), Roi Et Province (Suwannaphum District), Ubon Ratchathani Province (Na Chaluai District).
• Central Region. Lopburi Province (Lam Sonthi District).
• Eastern Region. Chonburi Province (Si Racha District).
• Western Region. Ratchaburi Province (Suan Phueng District), Prachuap Khiri Khan Province (Sam Roi Yot and Bang Saphan Noi Districts).
• Southern Region. Chumphon Province (Mueang Chumphon, Lang Suan, and Thung Tako Districts), Ranong Province (Kapoe District), Surat Thani Province (Ban Na San and Ko Pha-ngan Districts), Nakhon Si Thammarat Province (Phipun, Hua Sai, and Chawang Districts), Phuket Province (Thalang and Mueang Phuket Districts), Phatthalung Province (Si Banphot District), Trang Province (Kantang, Mueang Trang, Huai Yot, and Na Yong Districts), Songkhla Province (Ranot District), Satun Province (Mueang Satun, Tha Phae, and La-ngu Districts), Narathiwat Province (Sukhirin and Waeng Districts).

In preparation to handle the situation, relevant agencies are requested to take the following actions:

1. Continuously monitor weather and water conditions, especially areas with accumulated rainfall exceeding 90 millimeters within 24 hours and known flood-prone locations.

2. Monitor, inspect, and repair riverbank embankments; promptly remove waterway obstructions; and plan appropriate water management by adjusting operations of large, medium, and small reservoirs, river water levels, as well as drainage dams and gates to be consistent from upstream to downstream and consider tidal influences by accelerating drainage and releasing water to cope with expected heavy rains.

3. Prepare flood response plans, ensure readiness of personnel, machinery, and equipment to clear obstructions and dredge drainage systems, and integrate readiness to provide immediate assistance.

4. Publicize water situation updates and issue advance warnings so residents likely to be affected can prepare for timely evacuation if an emergency occurs.

Information courtesy of Facebook.National Water Resources Office.