REGIONAL SUMMARY:
During the forty-third week of 2025, a total of 32 disaster events were reported across the ASEAN region, including floods, landslides, storms, and wind-related incidents affecting Indonesia, Malaysia, Philippines, Thailand, and Viet Nam. In addition, widespread flooding caused by heavy rainfall and the overflow of rivers—first reported in Week 37—continued to be reported by the Department of Disaster Prevention and Mitigation (DDPM) in Phitsanulok, Sukhothai, Phichit, Nakhon Sawan, Uthai Thani, Chainat, Sing Buri, Ang Thong, Suphan Buri, Phra Nakhon Si Ayutthaya, Pathum Thani, Nonthaburi, Nakhon Pathom, Ubon Ratchathani, and Udon Thani Provinces. In Indonesia, Badan Nasional Penanggulangan Bencana (BNPB) recorded multiple disasters across Central Java, North Sumatra, Riau, West Java, East Java, North Maluku, Central Sulawesi, and South Sulawesi. In Malaysia, Agensi Pengurusan Bencana Negara (NADMA) reported flooding and Perak, Kedah, Pulau Pinang, and Sabah. In the Philippines, National Disaster Risk Reduction and Management Council (NDRRMC) reported flooding in North Cotabato, South Cotabato, and Sultan Kudarat in Region XII. In addition to the flooding from Week 37, the DDPM also reported new flooding events in Phuket, Surat Thani, and Chumphon. Finally, in Viet Nam, Viet Nam Disaster and Dyke Management Authority (VDDMA) reported floods, storms, landslides, and wind-related disasters in Quang Tri, Hue, Da Nang, Quang Tri, Quang Ngai, and Ho Chi Minh in Central and Southern Regions.
HIGHLIGHT:
Continuous moderate to heavy rainfall triggered widespread flooding across Semarang City, exacerbated by the overflowing Tenggang River, as reported by BNPB. Low-lying areas experienced water depths ranging from 20 to 80 centimeters, inundating roads, residential zones, and public facilities. BNPB reported a total of 42K people affected (about 22K households). Local and provincial disaster management agencies (BPBD) have deployed multiple pumps to drain floodwaters, supported by additional equipment from the Central Java government. Authorities continue to closely monitor weather conditions while ensuring the safety and provision of needs of affected communities.
HYDRO-METEO-CLIMATOLOGICAL:
For the past week, data from the ASEAN Specialised Meteorological Centre (ASMC) indicated medium to high 7-day average rainfall over Brunei Darussalam, Cambodia, Indonesia, Lao PDR, Malaysia, Myanmar, Philippines, Thailand, and Viet Nam. In addition to TC FENGSHEN, which is currently located over the Viet Nam East Sea (see Highlights section above for details), 2 tropical disturbances are being monitored for their potential impacts on the ASEAN region — INVEST 93B, located approx. 850 km northwest of Banda Aceh, and INVEST 95S, located approx. 355 km southwest of Padang. Both disturbances are expected to bring moderate to heavy rainfall over several provinces in Sumatra, Indonesia, before tracking away from ASEAN region (BMKG).
GEOPHYSICAL:
Five (5) significant earthquakes (M>5.0) were recorded by Indonesia’s Badan Meteorologi, Klimatologi, dan Geofisika (BMKG) and the Philippines Institute of Volcanology and Seismology (PHIVOLCS). Mount Marapi (alert level II), Semeru (alert level II), Lewotobi Laki-laki (alert level III), Merapi (alert level III) 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 PHIVOLCS.
OUTLOOK:
According to the ASEAN Specialised Meteorological Centre (ASMC), for the coming week, wetter conditions are predicted over southeastern Mainland Southeast Asia while drier conditions are predicted over the western and central equatorial region. Warmer than usual temperatures for this time of the year are predicted over the western and central equatorial region, in line with the predicted drier conditions. Warmer than usual temperatures are also predicted over western Mainland Southeast Asia. There is a moderate increase in chance of very heavy rainfall over Cambodia. There is also small increase in chance of very heavy rainfall over western Java. A negative IOD is currently present. La Niña conditions are predicted to become established in October 2025.
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Sources:
ASEAN Disaster Monitoring & Response System (DMRS); ASEAN Specialised Meteorological Centre (ASMC); Joint Typhoon Warning Centre (JTWC);
Indonesia: BNPB, BMKG, PVMBG;
Malaysia: NADMA;
Philippines: NDRRMC, PAGASA, PHIVOLCS;
Thailand: DDPM;
Viet Nam: VDDMA, NCHMF;
Various news agencies.
