
The Department of Disaster Prevention and Mitigation (DDPM) issued Cell Broadcast alerts to at-risk communities in Chiang Rai and Phayao on August 11, warning that rising rivers could overflow and affect riverside and low-lying areas.
The alerts covered communities along the Mae Lao River in Chiang Rai and the Rong Chang River in Phayao. Residents were advised to closely monitor water levels and prepare for possible flooding.
The Office of the National Water Resources Region 1 also forecast heavy to very heavy rain across northern Thailand from August 11–13, with more than 200 millimetres of accumulated rainfall expected in Pai district, Mae Hong Son.
The DDPM said the Mae Lao River was continuing to rise and could overflow its banks, affecting riverside communities, areas along tributaries and low-lying land.
Pa O Don Chai and San Sai subdistricts in Mueang Chiang Rai district, together with surrounding areas, were identified as being at particular risk.
Residents were advised to move belongings and vehicles to higher ground, secure valuables and important documents, beware of electric shock and ensure that vulnerable people were properly cared for.
The DDPM worked with mobile network operators AIS, True and NT to send the Cell Broadcast warning to people in the affected areas.
A separate Cell Broadcast alert warned that the Rong Chang River in Phayao was also continuing to rise and could overflow into riverside communities, areas along its tributaries and low-lying land.
The warning covered Bun Koet, Don Si Chum and Dok Kham Tai subdistricts in Dok Kham Tai district, as well as neighbouring communities.
People in the affected areas received the same advice to monitor water levels, move property and vehicles to safer locations, secure valuable items and documents, avoid electrical hazards and assist vulnerable residents.
The alert was distributed through the networks of AIS, True and NT.
The Office of the National Water Resources Region 1 identified areas at risk of heavy or very heavy rain during the three-day period.
Orange-level areas are forecast to receive more than 90mm of rain, while yellow-level areas are expected to receive between 35mm and 90mm.
For August 11, the forecast areas are:
Orange level — more than 90mm
Yellow level — 35–90mm
Very heavy rain is forecast in parts of Chiang Rai and Phayao on August 12.
Orange level — more than 90mm
Yellow level — 35–90mm
The forecast for August 13 places districts in Lampang, Phrae and Mae Hong Son at orange level.
Orange level — more than 90mm
Yellow level — 35–90mm
Pai district in Mae Hong Son was placed at red level for accumulated rainfall from August 11–13, with more than 200mm forecast over the three-day period.
Mueang Mae Hong Son and Pang Mapha districts were placed at orange level, with accumulated rainfall of between 150mm and 200mm expected.
Authorities warned that the rainfall could cause flash floods, landslides and flooding in low-lying areas. People in at-risk communities were urged to continue monitoring official updates.
Emergencies can be reported through the Line account “DDPM 1784 Emergency Reports” at @1784DDPM, or through the 24-hour DDPM hotline on 1784.