/ / Monthly Disaster Outlook



For the month of September 2021, a total of 161 disasters were reported. The ASEAN Member States that were affected were Cambodia, Indonesia, Lao PDR, Malaysia, the Philippines, Thailand and Viet Nam. Most of the disasters (69.57%) occurred in Indonesia but Thailand where only 7.45% of the total disasters for September 2021 occurred, comprised more than half of the total number of affected people (63.47%) for the month. The share of the disaster-affected people for other ASEAN Member States was as follows: (1) Cambodia-3.28%, (2) Lao PDR-0.01%, (3) Malaysia-0.03%, (4) Philippines-19.19%, and (5) Viet Nam-1.69%. September 2021 saw disasters affecting 433 per 100,000 people* and displacing 17 per 100,000 people* in the region, nearly five times and 17 times more than the previous month, respectively. September 2021 accounted for 17.65% of the total disasters reported so far in the current year.

Most of the disasters that occurred in September 2021 were floods (63.98%) and this is consistent with September of the previous year and September on a five-year average (2016-2020). September 2021 saw hydrometeorological disasters (drought, flood, rain-induced landslides, storm, winds) affecting 99.9% of the total affected persons for the month. The reported disasters in the region for September 2021 in comparison with the historical data (average for September 2016-2020) indicates that there were 6.44x more reported disasters; 1.45x more people affected; 1.95x fewer people displaced; 5.19x more houses affected to some extent; 1.14x more lives lost; 1.91x fewer people suffering injuries; and lastly, 3.7x fewer people reported missing.

Geophysically, 17 significant earthquakes (Magnitude ≥ 5.0) were reported by Indonesia’s Badan Meteorologi, Klimatologi dan Geofisika (BMKG), Myanmar’s Department of Meteorology and Hydrology (DMH), and the Philippine Institute for Volcanology and Seismology (PHIVOLCS). Recent volcanic activity was reported for Ili Lewotolok and Merapi (Alert Level III), Semeru, Dukono, Ibu and Krakatau (Alert Level II) in Indonesia by the Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG), and Taal (Alert Level 2) and Kanlaon (Alert Level 1) by PHIVOLCS. None have resulted in disasters but are being continuously monitored.

*Computed based on 2020 population data from worldometers.com



According to the ASEAN Specialised Meteorological Centre (ASMC), compared with the average value from 2001-2020, during September 2021, rainfall was above-average over much of the ASEAN region except for northern Sumatra, northern Philippines, parts of northern Myanmar, peninsular Malaysia, Borneo and Papua (which received rainfall from below- to near-average). The largest positive anomalies (wetter conditions) were detected over eastern mainland Southeast Asia for both satellite-derived rainfall estimate datasets (GSMaP-NRT and CMORPH-Blended). This is associated with the developments of Tropical Storm CONSON and Tropical Storm DIANMU which made landfall in early September and late September respectively. As a result, hydrometeorological disaster events were reported for numerous areas in Thailand and Viet Nam.



For the coming month of October, it is predicted that wetter conditions than normal will set in progressively in the ASEAN region due to the transition to intermonsoon conditions taking place. For the last quarter of the year (October to December), the prevailing southeasterly or southwesterly winds over the ASEAN region are expected to weaken prior to a change in direction to blow from the northeast or northwest.

For the upcoming quarter, according to the ASEAN Specialised Meteorological Centre (ASMC), there will be an increased chance of rainfall over much of the ASEAN region with the southern and eastern parts of the maritime continent having the highest likelihood for said conditions. Models are predicting La Niña-like conditions, but the tropical region of the Pacific has yet to show consistent La Niña-like conditions. The negative Indian Ocean Dipole (IOD) detected in the past month is forecast to return to neutral before December 2021. For this time of the year, a negative IOD tends to bring above-average rainfall in the southern ASEAN region. During the last quarter of 2021 also, warmer-than-usual temperatures are expected for much of the maritime continent. In the same period, the northeastern parts of mainland Southeast Asia are predicted to experience below- to near-normal temperatures associated with the northeast monsoon surges.

Considering the persistence of the negative IOD event until December 2021, the progressive settling of wetter conditions over the ASEAN region due to the transition to intermonsoon conditions, and the disaster data records from the ASEAN Disaster Information Network, the number of disaster events (particularly hydrometeorological disasters) and the affected persons, are expected to increase in frequency and number respectively, as the year ends. National Disaster Management Organisations (NDMOs), relevant authorities and agencies, and the public are advised to take necessary preparations and actions accordingly.

*Note from ASMC: The qualitative outlook is assessed for the region in general and based on the latest runs from models provided by the SEA RCC-Network LRF node. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.


Sources: ASEAN Disaster Information Network (ADINet), ASEAN Disaster Monitoring and Response System (DMRS), ASEAN Specialised Meteorological Centre (ASMC), Badan Nasional Penanggulangan Bencana (BNPB) – Indonesia, Agensi Pengurusan Bencana Negara (NADMA) – Malaysia, Department of Disaster Management (DDM) – Myanmar, National Disaster Risk Reduction and Management Council (NDRRMC) – Philippines, Department of Disaster Prevention and Mitigation (DDPM) – Thailand, Viet Nam Disaster Management Authority (VNDMA) – Viet Nam, Badan Meteorologi, Klimatologi dan Geofisika (BMKG) – Indonesia, Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) – Indonesia, Department of Meteorology and Hydrology (DMH) – Myanmar, Philippine Institute for Volcanology and Seismology (PHIVOLCS) – Philippines, Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) – Philippines

Written by : Keith Paolo Landicho, Sadhu Zukhruf Janottama, Lawrence Anthony Dimailig


The AHA Centre’s estimation is based on data and information shared by National Disaster Management Organisations (NDMOs) and other relevant agencies from ASEAN Member States, international organisations, and news agencies. Further information on each recorded significant disaster, description, and detail of data and information are available at: http://adinet.ahacentre.org/reports.