Heavy rain triggers reservoir and flood alerts in three Thai provinces
Nakhon Ratchasima warns of reservoir overflow risks, Lom Sak raises a red flag and Nan identifies districts under heavy and moderate rain watches.
- In Nakhon Ratchasima, authorities are releasing water from two reservoirs after 133mm of rain, warning residents of overflow risks and advising them to move belongings to higher ground.
- Phetchabun province has issued a "red flag" alert for Lom Sak as rising levels in the Pa Sak River threaten to flood low-lying areas.
- Nan province is on alert for flash floods and mudslides until September 20, with multiple districts under warnings for heavy to moderate rainfall.
Heavy rain affected many areas across Thailand on Wednesday (September 16, 2026), with waterlogging and flash floods reported in parts of the North and Northeast.
Authorities in Nakhon Ratchasima, Phetchabun and Nan issued warnings in response.
Korat warns of reservoir overflow risks
Nakhon Ratchasima issued a letter marked as most urgent to residents of Thepharak and Dan Khun Thot districts after 133 millimetres of rain sent large volumes of water into Thap Rang Reservoir and the Upper Lam Chiang Krai Reservoir.
Authorities accelerated water releases to lower reservoir levels.
Residents were advised to:
- Monitor the risk of waterways overflowing their banks in low-lying areas downstream of the reservoirs.
- Move belongings, property and pets to higher ground.
- Follow official announcements closely.
- Prepare to evacuate immediately if conditions become dangerous.
Lom Sak raises red flag as Pa Sak River rises
Irrigation authorities in Phetchabun instructed Lom Sak Municipality to raise a red flag after Pa Sak River levels were reported at 8am on Wednesday:
- Station S33 at Lom Kao: 5.97 metres, falling
- Station S53 at Ban Wang Rong Bridge: 4.55 metres, falling
- Station S3 at Lom Sak: 8.12 metres, rising
The Department of Disaster Prevention and Mitigation (DDPM) warned that accumulated rainfall upstream was sending water into the river and that levels were likely to continue rising.
The alert said areas outside flood embankments, low-lying parts of Lom Sak Municipality and neighbouring subdistricts would be affected.
Residents were advised to:
- Move belongings to higher ground.
- Relocate vehicles.
- Secure important documents and valuables.
- Beware of electrical hazards.
- Take particular care of vulnerable people.
People seeking assistance can contact:
- Disaster Prevention and Mitigation Office, Lom Sak Municipality: 056-701066 or 056-701080
- Emergency hotline: 08-6929-9993
- Public disaster emergency line: 199
Nan warns of flash floods and mudslides
The Nan Provincial Disaster Prevention and Mitigation Command Centre issued a letter marked most urgent on Tuesday (September 15, 2026), warning of flash floods, forest run-off and mudslides until Sunday (September 20, 2026).
Government agencies, district chiefs and local administrative organisations were instructed to prepare for emergencies and monitor conditions closely.
Areas under a yellow warning for heavy rain of 35.1 to 65.0 millimetres are:
- Tha Wang Pha district
- Song Khwae district
- Ban Luang district
- Mueang Nan district
- Phu Phiang district (No. 3)
- Mae Charim district
- Wiang Sa district
- Na Noi district
- Na Muen district
Areas under a green warning for moderate rain of 0.1 to 35.0 millimetres are:
- Chaloem Phra Kiat district (No. 1)
- Thung Chang district
- Chiang Klang district (No. 2)
- Pua district
- Bo Kluea district
- Santi Suk district
