The Chiang Rai Disaster Prevention and Mitigation Office issued an urgent warning that the Mae Sai River's water level is rising rapidly after rainfall in Myanmar. The water reached the deck of the First Mae Sai Border Bridge. Authorities are urgently inspecting and sealing leaks with big bags.
At approximately 12:29 on 10 Sep 2026, the Chiang Rai Disaster Prevention and Mitigation Office sent a warning message via Cell Broadcast to residents in Mae Sai district. Heavy rain in the upper watershed caused the Mae Sai River level at the First Friendship Bridge monitoring station to rise continuously.
The office warned residents living in low-lying areas along the Mae Sai River—including Wiang Pang Kham, Mae Sai, and Ko Chang subdistricts—to closely monitor potential river flooding. They were urged to move belongings to higher ground, watch over vulnerable groups such as the elderly and bedridden patients, and follow official updates continuously.
Inspection at the First Mae Sai Border Bridge revealed the Mae Sai River's water level had risen to the bridge deck. The water appeared reddish and muddy, flowing rapidly.
Mr. Warayut Khombun, Mae Sai district chief, and Mr. Anucha Yodchiangkam, mayor of Mae Sai municipality, led officials to inspect semi-permanent water barriers and big bag lines for leaks and areas where river currents had eroded the banks. Several critical risk points were found near Ban Ko Sai (at the old hotel beside the river near the bridge), where water was seeping into riverside shophouses. Officials quickly reinforced these leaks with big bags.
At the multipurpose ground in Ban Mai Lung Khon, strong currents eroded under the big bag barriers, causing minor bank collapses. Officials are urgently repairing these spots. Behind Wat Ko Sai temple, opposite the neighboring country's border wall, previously damaged areas had been repaired, but rising water levels nearly reached the top of the big bag barriers.
Mr. Warayut Khombun stated that around 10:00 a.m., heavy rain fell in the Jotada station area of Myanmar, causing a rapid surge of water into the Mae Sai River. The water seepage at the riverside shophouses has been contained and repaired by officials.
In addition, the Mae Sai municipality collaborated with community leaders to broadcast warnings urging residents to prepare. Residents in flood-prone areas who had experienced previous flooding have begun moving belongings to higher ground, preparing for possible flash floods and river overflows.
