Heavy Rain Floods Nan, Damages Weir and Collapses Bridge
Heavy rain across Nan province has damaged an irrigation weir, collapsed a bridge on Highway 1256, and forced evacuations in multiple districts since August 19, with over 200mm of rainfall triggering flash floods and waterway overflows.
NAN — 19 August 2026, Heavy rain has caused flooding across parts of Nan province, damaging an irrigation weir, washing out a bridge on a key route and prompting authorities to urge residents in at-risk areas to prepare to evacuate.
In Santi Suk district, one side of the Na Lao irrigation weir was washed away by strong currents, damaging the road beside it, the Nan provincial public relations office said. Persistent heavy to very heavy rain has caused waterways in the district to overflow, flooding homes, farmland and some roads. Ban Pang Chang in Pong subdistrict was among the affected areas.
As of 06:00, heavy rain was continuing. Flooding made the Phayaeng–Kiew Muang road, a route into Nan's provincial capital, impassable, officials said.
Authorities used a motorboat from Pa Laeo Luang Subdistrict Administrative Organisation to assist residents stranded near the water at Ban Sri Bun Rueang in Pong subdistrict. Strong currents hampered the operation. Residents were also stranded on a bridge over the Muap stream at Ban Nam Song in Du Phong subdistrict. Santi Suk district later reported that everyone on the bridge had been brought to safety.
Flooding was also reported in Pua, Chiang Klang and Tha Wang Pha districts, particularly around the Nam Pua and Nam Khuang waterways. A bridge on Highway 1256, the Pua–Bo Kluea route, reportedly collapsed, making the road impassable to all vehicles. Authorities advised travellers heading to Bo Kluea to use Highway 1081 via Santi Suk instead.
Nan municipality said more than 200mm of rain had fallen in several areas, particularly Pua, Santi Suk and Mae Charim districts, since midnight, causing flash flooding in northern parts of the province. Water levels in the Yao River and Wa River were rising.
The municipality urged residents in at-risk communities in Nan city, especially areas flooded in 2006 and 2024, to move belongings and vehicles to higher ground and prepare to evacuate vulnerable people. Those who decide to remain at home were advised to prepare at least three days' worth of food, drinking water and medicine, along with lighting, cooking and communication equipment. The municipality warned that electricity supplies could be suspended in some areas.
The Department of Disaster Prevention and Mitigation also urged authorities to move vulnerable residents, including elderly people and bedridden patients, to safer locations where necessary.
