REGIONAL SUMMARY:
During the thirty-eighth week of 2025, a total of 22 disaster events were reported across ASEAN region. These included droughts, floods, landslides, storms, and wind-related disasters affecting Indonesia, Malaysia, the Philippines, and Thailand. In Indonesia, Badan Nasional Penanggulangan Bencana (BNPB) recorded incidents in Banten, Bengkulu, West Java, Central Java, East Java, West Kalimantan, East Kalimantan, North Maluku, Central Sulawesi, and North Sulawesi. In Malaysia, Agensi Pengurusan Bencana Negara (NADMA) reported flooding and landslides in Sabah, Perak, Selangor, Negeri Sembilan, and Sarawak. In the Philippines, National Disaster Risk Reduction and Management Council (NDRRMC) reported disaster situations in SOCCSKSARGEN due to localized thunderstorms, as well as in Regions I, II, CAR, CALABARZON, MIMAROPA, III, V, VI, and IX, which were affected by the combined impacts of the Southwest Monsoon and Tropical Cyclones MITAG and RAGASA. Meanwhile, in Thailand, Department of Disaster Prevention and Mitigation (DDPM) documented storm in Amnat Charoen, in addition to flooding across 14 provinces which has continued from the previous week.
HIGHLIGHT:
During the thirty-eighth week of 2025, 2 significant tropical cyclones have affected ASEAN region and are expected to continue to have an impact in the coming days. These are Tropical Cyclones MITAG (Philippines local name “Mirasol”) and RAGASA (Philippines local name “Nando”). Together with the Southwest Monsoon, both TCs have brought impacts to the Philippines. According to PAGASA, MITAG entered the Philippine Area of Responsibility (PAR) on 16 Sep and made landfall over the Philippine landmass on 17 Sep as a tropical depression. RAGASA entered PAR on 18 Sep and, by 1600H UTC+7, had made landfall over Panuitan Island in Cagayan as a super typhoon equivalent to Category 4 on the Saffir-Simpson Hurricane Scale, before moving away from the Babuyan Islands.
According to the NDRRMC, as of 22 Sep at 0700H UTC+7, a total of 28,014 families or 100,024 persons had been affected. Of these, 187 families (541 persons) were served inside 10 ECs, while 173 families (722 persons) were served outside ECs. Reports also indicated 2 fatalities, 2 persons injured, and 5 persons missing, all for validation. Impacts on infrastructure included 29 road sections (4 still impassable), 22 bridges (4 still impassable), 1 airport (non-operational), and 12 seaports (4 non-operational). Furthermore, 21 houses were reported damaged, of which 14 were partially and 7 were totally damaged. As of 22 September, the NDRRMOC remains on Red Alert (Day 6). The NDRRMC continues to monitor the situation in close coordination with its member agencies and regional offices, and has activated the National Inter-Agency Coordination Cell together with selected National Response Clusters to support ongoing response operations.
As RAGASA is forecast to continue moving towards mainland Southeast Asia and is expected to make another landfall, other ASEAN Member States are closely monitoring its development. In Viet Nam, as of reporting, NCHMF forecasted landfall around 26 Sep over northern Viet Nam. In anticipation, the Deputy Prime Minister issued Official Dispatch No. 170/CD-TTg dated 22 September, directing ministries, agencies, and local authorities to take proactive measures in responding to RAGASA, with the aim of ensuring public safety and minimising potential impacts (VDDMA). 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 across Brunei Darussalam, Cambodia, Indonesia, Lao PDR, Malaysia, Myanmar, the Philippines, Thailand, and Viet Nam. As of reporting, RAGASA is forecast to continue moving west-northwest towards mainland Southeast Asia. According to PAGASA, RAGASA is expected to exit PAR on 23 Sep, while NCHMF has forecasted landfall over mainland Southeast Asia around 26 September.
GEOPHYSICAL:
Four (4) 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 IV), Ili Lewotolok (alert level III), Ibu (alert level II), and Dukono (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 much of the equatorial region and southwestern Maritime Continent. For the regional assessment of extremes, there is a low chance of very heavy rainfall or extreme heat conditions across the ASEAN region. 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 September
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, TMD;
Viet Nam: VDDMA, NCHMF;
Various news agencies.
