/ / Monthly Disaster Outlook



For the month of August 2023, a total of 99 disasters were reported. The ASEAN Member States that were affected are Cambodia, Indonesia, Lao PDR, Myanmar, Philippines, Thailand, and Viet Nam. Most of the disasters (59.6%) occurred in Indonesia and accounted for 42.66% of the affected persons (around 1M persons) the second-highest number of affected persons for August 2023. The Philippines accounted for most of the affected persons despite reporting only 12 disaster events — the Effects of Southwest Monsoon enhanced by Tropical Cyclone SAOLA, Tropical Cyclone HAIKUI, and Tropical Cyclone YUN-YEUNG with 46% of the total reported affected persons for the month of August 2023. The share of the disaster-affected people for the other ASEAN Member States are as follows: (1) Philippines-47.32%, (2) Indonesia-42.66%, Lao PDR-3.99%, Myanmar-3.04%, Cambodia-2.53%, Viet Nam-0.35%, and Thailand 0.1%. August 2023 saw disasters affecting 347 per 100,000 people* and displacing 11 per 100,000 people* in the region, which were almost 2 times lower respectively compared to the previous month.

Most of the disasters that have occurred in August 2023 were floods (46.5%) which is occurred in the northern sides of the equatorial line and is consistently the most recorded type of disaster for August of the previous year and August on a five-year average (2018-2022). However, due to the effects of El Nino, droughts are the second-highest disaster report (28%) for August 2023, especially in the southern parts of the equatorial line (Indonesia). The reported disasters in the region for August 2023 in comparison to the historical data (average for August 2018-2022) indicates that there were about 1.3x more reported disasters; 1.6x more people affected; 1.7x less people internally displaced; 1.9x less houses affected to some extent; 2.4x more lives lost; and 1x equal people suffering injuries.



Geophysically, 30 significant earthquakes (Magnitude ≥ 5.0) were reported by Indonesia’s Badan Meteorologi, Klimatologi dan Geofisika (BMKG) and the Philippine Institute for Volcanology and Seismology (PHIVOLCS) for the period of August 2023.

Mount Semeru (Alert Level ), Ili Lewotolok (alert Level ), Ibu (Alert Level ), and Dempo (Alert Level ) in Indonesia and Mayon (Alert Level 3), Taal (Alert Level 1), and Kanlaon Volcanoes (Alert Level 1) were reportedly tectonically active (erupting lava or releasing gas or generating seismic activity) throughout the month of August 2023.

As of 18 September PHIVOLCS maintained the Mayon Volcano Alert Level at Alert Level 3 (Increased Tendency Towards Hazardous Eruption). Mayon Volcano remains in a relatively high level of unrest as magma is at the crater and hazardous eruptions are possible within weeks or days. According to NDRRMC, as of 16 September 2023, 9.9K families (38.4K persons) have been affected and 13.6K persons remains internally displaced in 21 evacuation centres. The NDRRMC with other relevant-agencies/stakeholders have provided 7.7M USD worth of assistance to those affected.

*computed based on 2023 population data from worldometers.com



According to the ASEAN Specialised Meteorological Centre (ASMC), compared to the average value from 2001-2022, during August 2023, below-average rainfall was experienced in the central and southern parts of the Mainland Southeast Asia, and southern half of the Maritime Continent, while a mix of below-to above-average rainfall was experienced over the rest of the ASEAN region. The largest positive (wetter) anomalies were recorded over parts of western Myanmar, the largest negative (drier) anomalies were recorded over parts of Cambodia and southern Sumatra, parts of the Maluku Islands and southern Papua as shown in Figure 1. Particularly for the wetter conditions in the Philippines as shown in Figure 1, a MAJOR disaster was caused by the Effects of Southwest Monsoon enhanced by Tropical Cyclone SAOLA, Tropical Cyclone HAIKUI, and Tropical Cyclone YUN-YEUNG.



According to the ASEAN Specialised Meteorological Centre (ASMC), Southwest Monsoon conditions were observed in August 2023 and are expected to transition to the inter-monsoon period in the latter part of October 2023. These conditions traditionally bring light and variable winds and increased shower activities in the equatorial region as the monsoon rain-band shifts southwards into the region.

For the next 3 months, (September-October-November 2023), an increased chance of below-normal rainfall is predicted for most of the southern ASEAN region, extending to include the Philippines. El Niño conditions are predicted to strengthen and a positive Indian Ocean Dipole (IOD) is likely to develop in September 2023. Both El Niño conditions and positive IODs tend to bring drier conditions to parts of the ASEAN region. Above-normal temperature is predicted for most of the ASEAN region for September-October-November 2023.

Note: 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, Thai Meteorological Department (TMD) – TMD, Badan Meteorologi, Klimatologi dan Geofisika (BMKG) – Indonesia, Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG) – Indonesia, 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: https://adinet.ahacentre.org/report/