REGIONAL SUMMARY:
During the twenty-third week of 2026, a total of 14 disaster events were reported across the ASEAN region, including earthquakes, floods, landslides, storms, and wind-related disasters in Indonesia, the Philippines, Thailand, and Viet Nam. In Indonesia, Badan Nasional Penanggulangan Bencana (BNPB) reported disaster events across Aceh, North Kalimantan, North Maluku, South Sulawesi, Central Sulawesi, and North Sumatra. In the Philippines, National Disaster Risk Reduction and Management Council (NDRRMC) and Department of Social Welfare and Development (DSWD) reported M5.3 Earthquake in Region V. Meanwhile, in Thailand, Department of Disaster Prevention and Mitigation (DDPM) reported storms and wind in Phayao, Lamphun, Loei, Yasothon, Chaiyaphum, Surin, Udon Thani, Trat, Chachoengsao, and Krabi. Lastly, in Viet Nam, Viet Nam Disaster and Dyke Management Authority (VDDMA) reported storms and winds in Dien Bien and Son La.
HIGHLIGHT:
In Indonesia, heavy rainfall triggered flooding in Medan City, North Sumatra Province on 5 June, causing rivers to overflow and inundate residential areas across four sub-districts and five villages. According to BNPB, 2.2K families (6.9K people) were affected, with 30 people displaced to a church shelter. The flooding affected around 2K houses and disrupted access at six road sections. Medan City BPBD coordinated with relevant agencies to conduct assessments, monitor river water levels and weather conditions, prepare evacuation equipment, provide early warning advisories to residents, and distribute food assistance to affected communities and evacuees. As of 5 June, response operations were ongoing with support from local residents, while floodwaters had begun to gradually recede.
HYDRO-METEO-CLIMATOLOGICAL:
For the past week, data from the ASEAN Specialised Meteorological Centre (ASMC) indicated medium to high seven-day average rainfall across Brunei Darussalam, Cambodia, Indonesia, Lao PDR, Malaysia, Myanmar, Singapore, the Philippines, Thailand, and Viet Nam. During the reporting period, Tropical Disturbance INVEST 91W moved outside ASEAN and is forecast to continue tracking north-northeastwards, away from ASEAN region. (PAGASA, NCHMF, JTWC).
GEOPHYSICAL:
Seven (7) 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 II), Semeru (alert level III), Lewotobi Laki-laki (alert level III), and Ibu (alert level II) in Indonesia, and Taal (alert level 1), Mayon (alert level 3), Bulusan (alert level 1), and Kanlaon (alert level 2) 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 forecast over much of western and northern Mainland Southeast Asia, while drier conditions are expected across the southern Maritime Continent. Warmer-than-usual temperatures are predicted over the western Maritime Continent, eastern Mainland Southeast Asia, and parts of the northeastern Maritime Continent. For assessment of extreme, there is a slight increase in the likelihood of extreme rainfall across much of northern Mainland Southeast Asia, parts of coastal western Mainland Southeast Asia, and northeastern Borneo. Meanwhile, extreme hot conditions are forecast over parts of southern Mainland Southeast Asia and the western Maritime Continent. A moderate increase in the likelihood of extreme heat is predicted for northern Sumatra, while a slight increase is expected over southern Thailand, Cambodia, southern Viet Nam, northern Peninsular Malaysia, southern Sumatra, and western Java. In addition, a slight increase in the likelihood of extreme hot conditions is forecast for parts of the northern Philippines and southeastern Papua. A transition to El Nino conditions is predicted in June- July 2026.
Sources:
ASEAN Disaster Monitoring & Response System (DMRS); ASEAN Disaster Information Network (ADINet); ASEAN Specialised Meteorological Centre (ASMC); ASEAN Earthquake Information Centre (AEIC); Joint Typhoon Warning Centre (JTWC);
Indonesia: BNPB, BMKG, PVMBG;
Philippines: NDRRMC, PAGASA, DSWD, PHIVOLCS;
Thailand: DDPM, TMD;
Viet Nam: VDDMA;
Various news agencies.
