Tropical low-pressure system and monsoon trigger heavy rain and flash floods in northern Thailand
Tropical depression Bualoi downgraded as northern Thailand faces heavy rain, flash floods and landslides; rivers rise in Mae Hong Son.
The Thai Meteorological Department issued a weather advisory on Tuesday morning, reporting that tropical depression Bualoi has been downgraded to an active low-pressure system over Luang Namtha, Laos, while an active low-pressure cell covers upper Myanmar and upper Laos. The system is forecast to move through the monsoon trough across upper Myanmar and northern Thailand by September 30.
Bualoi is expected to strengthen the strong monsoon trough over northern Thailand and upper Myanmar, while the moderate to rather strong southwest monsoon prevails over the Andaman Sea, the South, Thailand’s Central region, the East, and the Gulf. Isolated heavy rain is likely nationwide, with accumulation potentially causing flash floods and river overflows, especially near foothills and low-lying areas.
Sea conditions:
Upper Andaman Sea and upper Gulf: waves 2-3 metres, exceeding 3 metres in thundershowers.
Lower Andaman Sea: waves around 2 metres, above 2 metres in thundershowers.
All vessels should navigate with caution, and small boats in the upper Andaman Sea and upper Gulf should remain ashore until September 30.
Flood situation in Mae Hong Son:
Worasak Panthong, District Chief of Mae Sariang, reported that the Yuam River has continued to rise, causing extensive damage to homes in Mae Hong Son. Landslides have buried houses following heavy rainfall on September 29, which triggered flash floods, rocks, and mudflows.
The flooding is among the most severe in decades, with rainfall measured at 131 mm in Mae Sariang town. Several roads were blocked by fallen trees, and authorities are actively responding to landslides and missing persons reports.
In Ban Pa Mak, Ban Kat Subdistrict, several homes and bridges have been damaged, making road access impossible. Local authorities are conducting continuous damage assessments.
In Ban Sai Khao, Huai Pha Subdistrict, flash floods carried rocks and mud into six houses and blocked roads. Authorities have since deployed tractors to clear the paths, restoring vehicle access.
Authorities continue to monitor the situation and urge residents to remain vigilant in affected areas.
