Sai River nears critical level after overnight rain in Chiang Rai
Authorities reinforce barriers near the Thai–Myanmar Friendship Bridge as residents in Mae Sai and Mae Fah Luang are urged to prepare for flash floods.
- Following heavy overnight rain, the Sai River in Mae Sai district reached a height of 4.01 metres, just 19 centimetres below its critical level of 4.20 metres.
- Authorities have issued a yellow (preparedness-level) alert for Mae Sai and Mae Fah Luang districts, advising residents in at-risk communities to prepare for potential river overflow and flash flooding.
- In response, municipal teams are reinforcing flood defences with large barrier bags along the riverbank to protect Mae Sai’s commercial district and residential areas.
- Officials are intensifying monitoring around the clock, as water levels could rise further if rain continues in upstream areas.
Heavy overnight rain pushed the Sai River in Mae Sai district to 4.01 metres on Friday morning, just 19 centimetres below the critical level of 4.20 metres, prompting Chiang Rai authorities to intensify monitoring.
Mae Sai and Mae Fah Luang districts were placed under a yellow, or preparedness-level, alert, with residents in at-risk communities advised to prepare for possible river overflow, flash flooding and run-off from higher ground.
The Public Relations Department’s Chiang Rai radio station reported at 8.30am on Friday (July 31) that persistent rain across the province overnight had caused water levels in major rivers and streams to rise rapidly.
Sai River approaches critical threshold
At 8am, the flash-flood and run-off monitoring centre operated by the Research, Development and Hydrology Division of the Department of Water Resources recorded the Sai River at 4.01 metres at the Ban Mae Sai gauge in Wiang Phang Kham subdistrict.
Upstream at Ban Cho Ta Da in Myanmar, accumulated rainfall reached 78.8 millimetres. The upstream monitoring station was at 76.67% of capacity, while the Sai River had risen to 95.06% of its warning level.
The river had not overflowed, but further run-off was continuing to move downstream. Water levels could rise further if rain persisted in upstream areas.
At Ban Samakkhi Mai in Mae Fah Luang subdistrict, the water level stood at 3.14 metres, below the critical mark of 4.50 metres. Officials nevertheless maintained close surveillance because run-off from the surrounding highlands could cause conditions to change rapidly.
Flood barriers reinforced near friendship bridge
Mae Sai subdistrict mayor Anucha Yodchiangkham and Mae Sai district chief Warayut Khombun inspected vulnerable sections beneath the First Thai–Myanmar Friendship Bridge as municipal teams moved to reinforce flood defences.
Engineering and disaster-prevention personnel deployed large flood-barrier bags to seal gaps at high-risk points along the riverbank. The barriers are intended to prevent the Sai River from spilling into Mae Sai’s commercial district and nearby residential communities.
No additional damage or newly affected areas had been reported as of 8.15am. Patrol teams were deployed to monitor water levels in real time around the clock.
Residents in at-risk locations were urged to move valuables, essential belongings and pets to higher ground and remain prepared for possible flash flooding or sudden run-off.
