REGIONAL SUMMARY:
During the thirty-seventh week of 2025, a total of 24 disaster events were recorded across ASEAN region, including droughts, flooding, landslides, storms, and wind-related disasters affecting Indonesia, Malaysia, the Philippines, Thailand, and Viet Nam. In Indonesia, Badan Nasional Penanggulangan Bencana (BNPB) reported incidents in Bali, Jakarta, Central Java, West Kalimantan, Central Kalimantan, East Kalimantan, Lampung, West Nusa Tenggara, East Nusa Tenggara, Southwest Papua, South Sulawesi, and Centrel Sulawesi. In Malaysia, Agensi Pengurusan Bencana Negara (NADMA) Malaysia reported flooding in Sabah and Sarawak. In the Philippines, the National Disaster Risk Reduction and Management Council (NDRRMC) and Department of Social Welfare and Development (DSWD) reported flooding in Regions XII and BARMM. Meanwhile, in Thailand, the Department of Disaster Prevention and Mitigation (DDPM) documented flooding across Phitsanulok, Phetchabun, Phichit, Nakhon Sawan, Uthai Thani, Chai Nat, Sing Buri, Ang Thong, Suphan Buri, Phra Nakhon Si Ayutthaya, Nakhon Pathom, and Chachoengsao. Lastly, Viet Nam Disaster and Dyke Management Authority (VDDMA) reported flooding, landslides, storms, and strong winds affecting Tuyen Quang, Lao Cai, Son La, Ha Tinh, Ca Mau, Dong Nai, and An Giang.
HIGHLIGHT:
In Indonesia, BNPB reported that heavy rainfall has triggered flooding in Bali Province, affecting Denpasar, Jembrana, Gianyar, Tabanan, Klungkung, Badung, and Karangasem since 9 September. As of 14 September at 1300H (UTC+7), BNPB reported 17 fatalities, 5 persons still missing, 6.3K people affected, and 375 people displaced. Reported damages include 194 houses, 520 public facilities, 3 collapsed bridges, 5 bridges affected, 82 breached retaining walls, 24 damaged boundary walls, 23 roads, 11 worship places, 4 educational facilities, 1 embankment breach, and 15 irrigation structures. The Province of Bali declared an emergency response status for extreme weather No. 810/04-G/HK/2025 from 10 to 17 September. At present, the floodwaters have receded, while BASARNAS and relevant agencies continue search operations for the missing persons.
Meanwhile, in Nagekeo, East Nusa Tenggara Province, flash flooding occurred following intense rainfall from 7 to 8 September. As of 14 September at 2345H (UTC+7), BNPB reported 6 fatalities, 3 missing persons, 2 injured, with 34.8K people affected and 73 families displaced. Reported damages include 33 houses, 1 educational facility, 1 worship place, 1 health facility, 1 government office, 8 bridges, 4.2 kilometres of damaged roads, 93.07 hectares of rice fields, and 1.15 hectares of plantations affected. The Nagekeo District Government has issued Decision No. 330/Kep/HK/2025 declaring an emergency status for extreme weather from 9 to 30 September 2025. Relevant government authorities have carried out necessary actions to address the situation.
HYDRO-METEO-CLIMATOLOGICAL:
For the past week, data from the ASEAN Specialised Meteorological Centre (ASMC) indicated high 7-day average rainfall concentrated across Brunei Darussalam, Cambodia, Indonesia, Lao PDR, Malaysia, Myanmar, the Philippines, Thailand, and Viet Nam. As of reporting, Tropical Disturbances INVEST 98W over the West Philippine Sea is being monitored for its potential development into a significant tropical cyclone. Global deterministic models are in agreement that INVEST 98W will move northwestward through the Viet Nam East Sea with little development (JTWC).
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 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; drier conditions are predicted over central and northeastern Mainland Southeast Asia; and cooler than usual temperatures are predicted over the southwestern Maritime Continent and parts of the central equatorial region. For the regional assessment of extreme weather events, there is a small increase in chance of very heavy rainfall conditions to occurs over Southwestern Maritime Continent. 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, DSWD;
Thailand: DDPM, TMD;
Viet Nam: VDDMA;
Various news agencies.
