For the thirty-fifth (35th) week of 2021, a total of 24 disasters (21 floods, 2 landslides, and 1 wind-related) affected the region. Indonesia, Malaysia, the Philippines, Thailand, and Viet Nam have reportedly been affected. Flooding caused by heavy rainfall and the overflowing rivers has been reported by Indonesia’s Badan Nasional Penanggulangan Bencana (BNPB) and Thailand’s Department of Disaster Prevention and Mitigation (DDPM). In Malaysia, heavy rainfall has caused flooding in different states as reported by the Agensi Pengurusan Bencana Negara (NADMA). Meanwhile in the Philippines, heavy rain due to the Inter-Tropical Convergence Zone was reported by the National Disaster Risk Reduction and Management Council (NDRRMC). Lastly, in Viet Nam, prolonged heavy rainfall caused flooding as reported by the Viet Nam Disaster Management Agency (VNDMA).
According to BNPB, prolonged moderate to heavy rainfall and the overflowing of rivers across Kalimantan from 1-3 September has caused flooding in several provinces and several regencies (Seruyan, Lamandau,
Murung Raya, and Barito Utara in Central Kalimantan; Melawi in West Kalimantan; Samarinda in East Kalimantan). In total, 12K families (23K persons) have been affected in Kalimantan. Reports of damages include 11 schools, 7 health facilities, 12 places of worship, and 6 government/public facilities. Local disaster management agencies have carried out necessary actions and continue to monitor and assess the situation as some areas remain under the risk of flooding as rain and floods persist.
For the past week, data from the ASEAN Specialised Meteorological Centre (ASMC) showed sparse high 7-day average rainfall across the ASEAN region. Tropical Cyclone advisories have been issued by the JTWC for TD 18W (local name: Jolina) and INVEST 94W. TD 18W is moving West-Northwestward and is forecast to move parallel to the east coast of the Philippines before its landfall as a low-pressure area in Northern Luzon on 10 Sep. 94W is moving northwestward and is not seen to have direct impacts to the region.
Two (2) significant earthquakes (M≥5.0) were recorded in the region by Indonesia’s Badan Meteorologi Klimatologi dan Geofisika (BMKG) and the Philippine Institute for Volcanology and Seismology (PHIVOLCS). Volcanic activity was reported for Mount Semeru and Ibu (Alert level II) in Indonesia according to Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) and Taal Volcano (Alert Level 2), and Mount Kanlaon (Alert Level 1) according to PHIVOLCS.
According to the ASMC, for the coming week, wetter conditions should be expected over the central and eastern Maritime Continent, most of Mainland Southeast Asia, and the Northern parts of the Philippines. Warmer temperatures should be expected over the Southern Maritime Continent. For the regional assessment of extremes, there is a small chance for a very heavy rainfall event to occur in parts of Southern Mainland Southeast Asia, southern tip of the Philippines, and eastern Borneo; moderate increase in chance for parts of central and eastern Maritime Continent. There is also a moderate increase in chance for extreme hot conditions to occur in the Southern Maritime Continent. A negative Indian Ocean Dipole (IOD) has developed in the Indian Ocean, with warmer sea surface temperatures. At a seasonal timescale, negative IOD events tend to bring wetter conditions to the Southern Maritime Continent.