FLASH UPDATE #1 – Transboundary Flooding and Landslides
Countries under monitoring: Lao PDR and Thailand
OVERVIEW
Heavy and continuous rainfall have caused extensive flooding in several provinces in the upper regions along the border of Lao PDR and Thailand. On 23 August, the National Disaster Management Office (NDMO) Lao PDR reported flooding situation in 6 districts of Xayaboury Province that started since 20 August 2024. Meanwhile, since 16 August, the Department of Disaster Prevention and Mitigation (DDPM) Thailand has reported flooding in 6 provinces in the Northern Region. Persistent and heavy rainfall caused rivers to overflow and flooding has extended to 11 provinces. On 20-23 August, flash floods and landslides have been reported in several provinces in Northern, Northeastern, and Southern Regions of Thailand. Based on the report from the DDPM Thailand on 23 August 2024 at 1800H UTC+7, these disaster situations still persist in 8 provinces.
LAO PDR
IMPACTS: According to NDMO Lao PDR, heavy rainfall resulted to flooding in Xayabouri Province that affected 6 districts (Khorb, Hongsa, Ngeun, Xienghon, Phieng, Xaysathan), 5 villages, 80 families (about 400 individuals). Damage to agriculture and infrastructure have also been reported, data validation is ongoing.
RESPONSE: Provincial authorities have been conducting response operations and are closely coordinating with the NDMO Central for support. National and provincial authorities are closely monitoring the situation and supporting the affected communities. Data collection and damage assessment are ongoing. All information are being monitored closely by the Central and Provincial authorities.
THAILAND
IMPACTS: According to the report of DDPM dated 23 August 2024 at 1800H UTC+7, from 16-23 August 2024, there have been flooding situations in 11 provinces (Chiang Rai, Chiang Mai, Phayao, Nan, Lampang, Phrae, Phetchabun, Udon Thani, Rayong, Phuket, Yala) 62 districts, and 255 sub-districts. A total of 30,598 households (about 153K individuals) have been affected, of which, 21.8K households (about 109K individuals) are still currently affected. In Phuket, flooding and landslides have resulted to 10 deaths (6 female, 4 male), 1 missing (female), and 19 injured persons.
RESPONSE: The Provincial Disaster Prevention and Mitigation Office, the local military units, police officers, local administrative organisations, village defense volunteers, volunteer organisations, and relevant agencies inspected the damage and provided assistance by laying sandbags and installing water pumps to quickly drain water from the affected areas. Assistance and relief items were also distributed to affected communities. Incident command centres were set up to coordinate and provide assistance. Authorities deployed high-performance and specialised vehicles, rescue boats and trucks, heavy equipment and disaster relief machinery to support the response operations. According to DDPM Thailand, the flooding situations are under control and water levels are decreasing.
ANTICIPATED RISKS
- According to Thailand Meteorological Department (TMD) 24hr forecast dated 24 August 2024, the monsoon trough passes through the upper part of the North and upper Laos, entering a low-pressure cell in the upper part of Viet Nam. In addition, there is a test line of southeasterly and southwesterly winds at the upper level covering the North and Northeastern regions. Meanwhile, the southwest monsoon may cause heavy rain in some areas of the North, upper Northeast, East and lower South.
- Heavy rain and accumulated rain in these areas may cause flash floods and forest runoff, especially in areas on slopes near waterways and lowlands.
- The Southwest Monsoon is forecast to strengthen and may bring heavy and continuous rainfall in Northern, Eastern, Upper Northeastern, Central, and Southern Regions in Thailand from 24-30 August. Warnings of potential flash floods have been issued. (TMD).
- According to the Mekong River Commission (MRC), heavy rainfall may occur in Bokeo, Luangnamtha, Xayaboury, Luangprabang, Oudomxay, Phongsaly, Xaysomboun, and Vientiane in Lao PDR; and Chiang Rai, Loei, Nong Khai, Bueng Kan, Sakon Nakhon and Nakhon Phanom in Thailand.
- According to generated models, flash floods may occur in some areas of Bokeo, Luangnamtha, Luangprabang, Xayaboury, and Oudomxay (Lao PDR).
- Mekong River Flood Forecast from 24-29 August indicates Alarm Level at 3 stations (Vientiane in Lao PDR, and Chiang Khan and Nong Khai in Thailand). (MRC)
THE AHA CENTRE
The AHA Centre will continue to monitor for further developments and issue necessary updates.
DATA SOURCES
ASEAN Disaster Monitoring & Response System (DMRS), ASEAN Disaster Information Network (ADINet); Pacific Disaster Center (PDC Global); ASEAN Specialised Meteorological Centre (ASMC);
Lao PDR: NDMO Lao PDR;
Thailand: DDPM, TMD;
Verified news media agencies;
