Indonesia + 2 more

ASEAN Weekly Disaster Update Week 33, 16 – 22 August 2021



For the thirty-third (33rd ) week of 2021, a total of 14 disasters (12 floods and 2 landslides) affected the region. Indonesia, Malaysia, and the Philippines have reportedly been affected. Flooding caused by heavy rainfall and the overflowing rivers as well as coastal flooding has been reported by Indonesia’s Badan Nasional Penanggulangan Bencana (BNPB). In Malaysia, heavy rainfall has caused flooding and landslide in different states as reported by the Agensi Pengurusan Bencana Negara (NADMA). Meanwhile in the Philippines, a landslide event was reported in Itogon, Benguet as reported by the Department of Social Welfare and Development (DSWD).


According to BNPB, heavy rainfall and the overflowing of rivers on 16 Aug have affected Batu Bara and Asahan Regencies in North Sumatra. In Batu Bara, 5.9K families (23.6K persons) were affected and 5.9K houses and 5.3K ha of rice fields were damaged. In Asahan, 3.3K families (16.6K persons) were affected and 510 were displaced and 3.3K houses, 5 schools, a health facility, 3 public buildings, and 4 worship places were damaged.
Flooding has already reportedly receded in both regencies. In North Sumatra as well, flooding occurred in Medan City on 20 Aug. Heavy rainfall has caused the Deli River to overflow causing a flood that affected 578 families (2.1K persons) and damaged 507 houses. The flood has already reportedly receded and local disaster management agencies have responded accordingly.


For the past week, data from the ASEAN Specialised Meteorological Centre (ASMC) showed sparse high 7-day average rainfall across Peninsular and Eastern Malaysia, Northwestern Philippines, Sumatra, and in several parts of the Maritime Continent. Currently, there is an active tropical cyclone being monitored—TS OMAIS (ISANG) but has no direct impacts to the region. Other than TS OMAIS (ISANG), there are no other tropical cyclone advisories according to JTWC.


One (1) significant earthquake (M≥5.0) was recorded in the region by Indonesia’s Badan Meteorologi Klimatologi dan Geofisika (BMKG). Ili Lewotolok and Merapi in Indonesia (Alert level III) reported recent volcanic activity and are under close monitoring. Volcanic activity was also reported for Mount Semeru and Ibu 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 the Philippine Institute for Volcanology and Seismology (PHIVOLCS).


According to the ASMC, for the coming week, wetter conditions should be expected over most of the central and eastern Maritime Continent; Warmer temperatures over the southern Maritime Continent and cooler temperatures parts of the equatorial region and Philippines are forecasted for the coming week. For the regional assessment of extremes, there is a small increase in chance for a very heavy rainfall event in the southeastern coastal parts of Mainland Southeast Asia and parts of Eastern Borneo and moderate increase in chance in parts of southeastern Maritime Continent; small increase in chance for extended dry conditions in Northwest Sumatra; moderate increase in chance for extreme hot conditions in Western Mainland Southeast Asia and very likely in the Southern Maritime Continent; small increase in chance for extreme cold conditions in Northeast Philippines.