REGIONAL SUMMARY:
During the thirty-ninth week of 2025, a total of 29 disaster events were reported across ASEAN region. These included tropical cyclones, floods, landslides, storms, and wind-related events that affected Indonesia, the Philippines, Thailand, and Viet Nam. In Indonesia, Badan Nasional Penanggulangan Bencana (BNPB) recorded incidents in Central Sulawesi, North Sumatra, West Java, South Sumatra, North Maluku, and South Sulawesi. In the Philippines, National Disaster Risk Reduction and Management Council (NDRRMC) reported the combined effects of the Southwest Monsoon, Tropical Cyclones MITAG, RAGASA, and BUALOI, and associated hazards such as floods, landslides, storms, and strong winds in Regions I, II, CAR, NCR, CALABARZON, MIMAROPA, V, VI, NIR, IX, and BARMM. In Thailand, the Department of Disaster Prevention and Mitigation (DDPM) reported that flooding from Week 37 has persisted and affected 17 provinces. Finally, the Viet Nam, Disaster and Dyke Management Authority (VDDMA) reported impacts of local storms and Tropical Cyclone BUALOI in the Central and Northern Regions.
HIGHLIGHT:
In Week 39 of 2025, Tropical Cyclone BUALOI caused severe impacts across the ASEAN region. In the Philippines, the NDRRMC (Situational Report No. 29) reported that due to the combined effects of Southwest Monsoon, TCs MITAG, RAGASA, & BUALOI, a total of 3,420,391 people (906,764 families) were affected across 16 Regions. Casualties include 27 deaths, 33 injuries, and 16 missing persons, while 190,801 people are currently displaced. Among damages reported were 16,911 houses (2,600 totally damaged), 287 road sections, 55 bridge sections, and 36,926.012 hectares of crops. As of 0500H UTC+7 today, a total of 659 areas are flooded along 37 related incidents including collapsed structure, landslides, and destructive winds. After crossing central Philippines, BUALOI made landfall in Viet Nam’s Northern Central Region, where VDDMA’s initial report indicated 2 deaths, 4 missing, 2 injuries. In addition, 17 people had lost contact due to maritime incidents. At least 245 houses were unroofed, 19 flooded, and 1,387 hectares of crops damaged.
Hundreds of thousands have been pre-emptively evacuated to ensure safety of communities in high risk areas. Authorities are actively responding to the impacts of the tropical cyclone, providing urgent needs to the affected communities and displaced population. Debris clearing, search and rescue, and distribution of food and non-food items are underway.
The AHA Centre continues to closely monitor the situation, in coordination with the affected and potentially affected ASEAN Member States, and stands ready to provide support should the need arise.
HYDRO-METEO-CLIMATOLOGICAL:
For the past week, data from the ASEAN Specialised Meteorological Centre (ASMC) indicated medium to high 7-day average rainfall concentrated across Brunei Darussalam, Cambodia, Indonesia (Sumatra, Kalimantan, Sulawesi, Maluku, Papua), Lao PDR, Malaysia, Myanmar, the Philippines, Thailand, and Viet Nam. Notable high-average rainfall was observed in the Philippines and western mainland Southeast Asia due to Tropical Cyclones RAGASA and BUALOI. As of reporting, another area of convection, INVEST 93W, is being monitored about 1,626 km east of the Philippines. According to JTWC, INVEST 93W currently has low potential to develop into a tropical cyclone within 24 hours.
GEOPHYSICAL:
Six (6) significant earthquakes (M?5.0) were recorded by Indonesia’s Badan Meteorologi, Klimatologi, dan Geofisika (BMKG). Sinabung (alert level II), Marapi (alert level II), Dempo (alert level II), Anak Krakatau (alert level II), Slamet (alert level II), Merapi (alert level III), Semeru (alert level II), Bromo (alert level II), Raung (alert level II), Lewotobi Laki-Laki (alert level IV), Ili Lewotolok (alert level III), Soputan (alert level II), Lokon (alert level III), Ruang (alert level II), Gamalama (alert level II), and Ibu (alert level II) in Indonesia, and Kanlaon (alert level 2), Taal (alert level 1), Mayon (alert level 1), and Bulusan (alert level 1) volcanoes in the Philippines reported recent volcanic activity according to Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) and Philippines Institute of Volcanology and Seismology (PHIVOLCS).
OUTLOOK:
According to the ASEAN Specialised Meteorological Centre (ASMC), for the coming week, wetter conditions are predicted over much of the central and southern Maritime Continent. There is a small increase in chance of very heavy rainfall over the northern parts of Mainland Southeast Asia, including northern Viet Nam, northern Lao PDR, and parts of northeastern Myanmar, related to Tropical Storm Bualoi. There is a small increase in chance of extreme hot conditions over central Viet Nam. While ENSO neutral conditions have been present, models predict potential for La Niña conditions to develop in the coming months. There are also signs that a negative Indian Ocean Dipole has developed, with models predicting negative IOD conditions in October.
Sources:
ASEAN Disaster Monitoring & Response System (DMRS); ASEAN Specialised Meteorological Centre (ASMC); Joint Typhoon Warning Centre (JTWC);
Indonesia: BNPB, BMKG, PVMBG;
Philippines: NDRRMC, PAGASA, PHIVOLCS;
Thailand: DDPM, TMD;
Viet Nam: VDDMA, NCHMF;
Various news agencies.
