Department of Disaster Prevention Warns All Provinces to Watch for Flash Floods and Flash Flooding Until 21 May 2026

The Department of Disaster Prevention and Mitigation (DDPM) has advised all provinces and Bangkok to remain vigilant for flash floods, sudden flooding, and waterlogging. Meanwhile, six southern provinces are to watch for strong waves and winds during 19 to 21 May 2026.

On 20 May 2026, Mr. Theerapat Kachamat, Director-General of the Department of Disaster Prevention and Mitigation, revealed that the Central Disaster Prevention and Mitigation Command has been monitoring weather conditions and risk factors. This follows the Meteorological Department's announcement of heavy to very heavy rain over Thailand and strong waves in the Andaman Sea, Announcement No. 12 (72/2569), effective through 21 May 2026, issued on 18 May 2026 at 17:00.

It was reported that from 19 to 21 May 2026, Thailand will experience increased rainfall, including some very heavy rain, mainly in the western parts of the North, Northeast, Central, and western Southern regions. This is due to a fairly strong southwest monsoon covering the Andaman Sea, Thailand, and the Gulf of Thailand, combined with a low-pressure area over the northern coast of the Socialist Republic of Vietnam. Areas expected to face heavy rain may experience flash floods, sudden flooding, waterlogging, and strong waves from 19 to 21 May 2026, detailed as follows.

Areas to monitor for flash floods, sudden flooding, and waterlogging.

• Northern region: 17 provinces including Mae Hong Son, Chiang Mai, Chiang Rai, Lamphun, Lampang, Phayao, Phrae, Nan, Uttaradit, Tak, Sukhothai, Kamphaeng Phet, Phitsanulok, Phichit, Phetchabun, Nakhon Sawan, and Uthai Thani.
• Northeastern region: 20 provinces including Loei, Nong Khai, Bueng Kan, Nong Bua Lamphu, Udon Thani, Sakon Nakhon, Nakhon Phanom, Chaiyaphum, Khon Kaen, Maha Sarakham, Kalasin, Mukdahan, Roi Et, Yasothon, Amnat Charoen, Nakhon Ratchasima, Buriram, Surin, Sisaket, and Ubon Ratchathani.
• Central region: 25 provinces including Kanchanaburi, Ratchaburi, Suphan Buri, Chai Nat, Sing Buri, Ang Thong, Phra Nakhon Si Ayutthaya, Lopburi, Saraburi, Nakhon Nayok, Prachin Buri, Sa Kaeo, Chachoengsao, Chonburi, Rayong, Chanthaburi, Trat, Phetchaburi, Prachuap Khiri Khan, Pathum Thani, Nonthaburi, Nakhon Pathom, Samut Sakhon, Samut Songkhram, and Samut Prakan.
• Southern region: 14 provinces including Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala, Narathiwat, Ranong, Phang Nga, Phuket, Krabi, Trang, and Satun.

Areas to monitor for strong waves and winds.

• Southern region: six provinces including Ranong (Mueang Ranong, Suk Samran, and Kapoe districts), Phang Nga (Ko Yao, Takua Thung, Thai Muang, Takua Pa, and Kuraburi districts), Phuket (all districts), Krabi (Mueang Krabi, Khlong Thom, Ko Lanta, Nuea Khlong, and Ao Luek districts), Trang (Kantang, Sikao, Palian, and Hat Samran districts), and Satun (Mueang Satun, La-ngu, Tha Phae, and Thung Wa districts).

The Central Disaster Prevention and Mitigation Command under the Department of Disaster Prevention and Mitigation has coordinated with all provinces and regional disaster prevention centers to prepare for increased rainfall and heavy to very heavy rain. They have instructed officials to closely monitor weather, rainfall, and water conditions and to deploy operational teams with disaster machinery to high-risk areas for prompt response and assistance, especially where rainfall exceeds 90 millimeters within 24 hours.

In frequently flooded risk areas, water drainage should be accelerated to minimize impacts. For natural tourist sites, especially caves and waterfalls, if risks arise, warnings should be issued and access restricted. In cases of strong waves and winds, related agencies should issue alerts or install warning signals along coastlines, strictly prohibiting tourists from swimming. Fishermen, boat operators, and passenger vessel services should be advised to exercise increased caution while navigating.

If conditions worsen, authorities should consider a total ban on navigation and assign personnel to monitor risk areas and provide immediate assistance around the clock. Provinces are urged to publicize weather updates and official news closely and to alert residents in vulnerable areas in advance so they can prepare and strictly follow government guidance.

At this time, the public is advised to continuously follow weather updates, warning announcements, local water conditions, and official news through the "THA DISASTER ALERT" application. For emergency assistance, contact via the LINE account "DDPM Emergency 1784" or the 24-hour safety hotline 1784 for coordination and support.