GENERAL REVIEW OF OCTOBER 2023

For the month of October 2023, a total of 77 disasters were reported in the ASEAN region. The number of reported occurrences was 2.8x less than the number of reported disasters in October of the last year. The ASEAN Member States affected for October 2023 were Indonesia, Malaysia, Myanmar, Philippines, and Viet Nam. Majority of the disaster (62.34%) occurred in Indonesia and accounted for 86.48% of the affected persons (about 320K persons) and 66.75% of affected houses (around 11.35K houses) for this reporting period. The share of the affected people for the ASEAN Member States are as follows: (1) Indonesia – 86.48%, (2) Viet Nam – 5.31%, (3) Philippines – 4.70%, (4) Myanmar – 3.29%, and (5) Malaysia – 0.23%. With the decrease in the number of significant disasters in October 2023, 54 per 100,000 people* were affected which was about 4x less than the number of affected persons last month. Meanwhile, about 3 per 100,000 people* in the region have been displaced, which was 1.6x less compared to the previous month.

Out of the total disasters in October 2023, flood accounted for the highest percentage of occurrence at 40.26%. Flood had been consistently the most recorded type of disaster in the region but the recorded floods for October 2023 is 1.9x less than the five-year average (2018-2022) for October and 4.9x less than the flood incidents in October of the last year. Wind disasters ranked second with 20% of the reported disasters in October 2023. The reported floods and wind disasters were generally attributed to continuous rains and strong winds associated with the monsoons and enhanced by two tropical cyclones (Tropical Cyclone KOINU and SANBA) that passed by the region and affected the Philippines and Viet Nam at the start and in the middle of October 2023. While floods had been the most recorded disaster for this period, drought, which accounted for 18.18% of recorded disasters in October 2023, had the most number of affected persons at 74.90% (about 277K persons) in Indonesia. The decreasing rainfall and water supply were associated with the effects of El Niño that had affected the region, particularly in the southern portions of the equatorial line. The reported droughts for this reporting period was 14x more than the five-year (2018-2022) average for the month of October. Overall, compared to the historical data (average for October 2018-2022), the available data on the disasters and associated impacts for the month of October 2023 indicates 1.19x less reported disasters, 9.4x less affected people, 5.9x less people internally displaced, 9.6x less houses affected to some extent, 8.5x less lives lost, and 27.8x less people suffering injuries.

GEOPHYSICAL CONDITION FOR OCTOBER 2023

Geophysically, 26 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 October 2023.

Mounts Ibu (Alert Level II), Semeru (Alert Level III), Dukono (Alert Level II), Ili Lewotolok (Alert Level II) in Indonesia and Mayon (Alert Level 3), Taal (Alert Level 1), and Kanlaon (Alert Level 1) in the Philippines were reportedly tectonically active (erupting lava or releasing gas or generating seismic activity) throughout the month of October 2023.

On 12 October 2023, PHIVOLCS released a notice of increased and continuous degassing activity from Taal Volcano with 9,762 tonnes/day of volcanic sulfur dioxide gas emission from Taal Main Crater. This was the highest recorded SO2 emission from Taal for the year 2023 at the time, which was 2.6x the average SO2 emission of 3,781 tonnes/day since September 2023. According to PHIVOLCS, the prevalence of Alert Level 1 indicated that Taal remained in abnormal condition and may cause sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfalls and lethal accumulations or expulsions of volcanic gas.

*computed based on 2023 population data from worldometers.com

ANALYSIS

According to the ASEAN Specialised Meteorological Centre (ASMC), the Southwest Monsoon gradually transitioned into inter-monsoon conditions from the end of October 2023. As monsoon rainband moved towards the equator, the prevailing winds weakened and turned light and variable over the equatorial regions as shown in Figure 1. In addition, Tropical Cyclone KOINU which tracked northeast to north of the Philippines brought about heavy rainfall and strong winds over the northern regions of the Philippines. Above-average to high rainfall also accumulated over the Central and Northern Central Regions of Viet Nam, which was attributed to Tropical Cyclone SANBA in the middle of October 2023 and brought about landslides and flooding in these areas. Towards the end of October, Tropical Cyclone HAMOON brought above average rainfall along the coastal areas of Rakhine Territory in Myanmar before making landfall in Bangladesh. Meanwhile, dry weather persisted over much of the southern ASEAN region for the first half of October, while an increase in showers over parts of southern Kalimantan and southern Sumatra occurred towards the end of October. Most of Java and Sulawesi in Indonesia have remained dry and these conditions had been associated with the drought disasters that had occurred and affected about 277K persons in these areas.

SEASONAL OUTLOOK

According to the ASEAN Specialised Meteorological Centre (ASMC), the Southwest Monsoon transitioned into the inter-monsoon period from the end of October 2023. Prevalence of the inter-monsoon conditions may be expected over the ASEAN regions in November, where the prevailing winds are light and variable in direction over most parts of the region. An increase in shower activities is also likely with the monsoon rainband located close to the equator. Gradual onset of the Northwest Monsoon can be expected from December, during which the prevailing winds over the ASEAN region blow predominantly from the northwest or northeast.

An increased chance of below-normal rainfall is predicted for November 2023 to January 2024 over the southern and eastern Maritime Continent. Meanwhile, the northwestern Maritime Continent is likely to have above-normal rainfall. The ocean indicators (Nino3.4 index) shows El Niño conditions with support from key indicators (cloudiness, trade wind). El Niño conditions are likely to persist until at least February to March 2024. ASMC notes the presence of a positive Indian Ocean Dipole (IOD) which is predicted to end by January to February 2024. Both El Niño and positive IOD tend to bring drier conditions to much of the region. For the period of November 2023 to January 2024, ASMC predicts above-normal temperature for most of the ASEAN region.

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 : Jasmine Alviar, Sadhu Zukhruf Janottama, Lawrence Anthony Dimailig

GENERAL REVIEW OF SEPTEMBER 2023

For the month of September 2023, a total of 111 disasters were reported. The number of reported occurrences was 42.49% less than the number of reported disasters in September of the last year. The ASEAN Member States affected for September 2023 were Cambodia, Indonesia, Myanmar, Philippines, Thailand, and Viet Nam. Most of the disasters (54.95%) occurred in Indonesia and accounted for 43.6% of the affected persons (around 670K persons), the highest number of affected persons for this reporting period. The share of the disaster-affected people for the other ASEAN Member States are as follows: (1) Indonesia – 43.62%, (2) Philippines – 28.07%, (3) Thailand – 14.16%, (4) Cambodia – 13.13%, (5) Viet Nam – 0.42%, (6) Myanmar – 0.39%, and (7) Malaysia – 0.21%. September 2023 saw disasters affecting 223 per 100,000 people* and displacing 5 per 100,000 people* in the region, which was significantly lower (36% and 58%, respectively) compared to the previous month.

Out of the total reported disasters in September 2023, 48.65% was flood which mostly occurred in the northern hemisphere and consistently the most recorded type of disaster for the month of September of the previous year and September on a five-year average (2018-2022). However, due to the effects of El Niño, drought ranked as the second most reported disaster (29.73%), particularly in the southern parts of the equatorial line (Indonesia) for September 2023. The reported number of droughts (33) was 33x more than the reported drought in September of the previous year (1) and 15.5x more than the five-year (2018-2022) average for drought in September (2). While the reported disasters in the region for September 2023 in comparison with the historical data (average for September 2018-2022) indicates 1.5x more reported disasters, there were 2.7x less affected people, 4.2x less people internally displaced, 1.6x less houses affected to some extent, 13.4x less lives lost, and 281x less people suffering injuries.

GEOPHYSICAL CONDITION FOR SEPTEMBER 2023

Geophysically, 22 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 September 2023.

Mounts Ibu (Alert Level II), Semeru (Alert Level III), Dukono (Alert Level II), Ili Lewotolok (Alert Level II) in Indonesia and Mayon (Alert Level 3), Taal (Alert Level 1), and Kanlaon (Alert Level 1) in the Philippines were reportedly tectonically active (erupting lava or releasing gas or generating seismic activity) throughout the month of September 2023.

As of 1 October, PHIVOLCS maintained the Mayon Volcano at Alert Level 3 (Increased Tendency Towards Hazardous Eruption). According to PHIVOLCS, there have been volcanic earthquakes, rockfall events, and pyroclastic density current events still within the 4-km radius from the crater. Volcanic sulfur dioxide (SO2) emissions averaged 1392 tonnes/day for September 2023 and hazardous eruption within weeks could still be possible. According to NDRRMC’s report on 11 October, a total of 9,876 families or 38,396 persons were affected. Of which, 52 families (195 persons) remain displaced inside 1 evacuation centre. The NDRRMC with other relevant-agencies/stakeholders have provided 7.9M USD worth of assistance to those affected.

*computed based on 2023 population data from worldometers.com

ANALYSIS

According to the ASEAN Specialised Meteorological Centre (ASMC), the Southwest monsoon conditions persisted over the region in September 2023. ASMC noted that the prevailing low-level winds blew mainly from the southeast from the south of the equatorial line and turned to blow from the southwest or west over areas north of the Equator Dry conditions prevailed over many parts of southern ASEAN region as the area remained under the traditional dry season. Isolated showers were recorded over parts of northern Sumatra, Malayasia, and northeastern Kalimantan. Over the northern ASEAN region, the weather was generally wet as the traditional wet season prevailed. The average daily rainfall and mean winds in the region for September 2023 are illustrated in Figure 1. Moderate to heavy rainfall concentration over the northern and northeastern parts of Thailand and north, northwestern, and central provinces of Cambodia, especially those in low-lying areas and near river systems, may have contributed to the flooding events that affected 69K families in these areas.

SEASONAL OUTLOOK

According to the ASEAN Specialised Meteorological Centre (ASMC), the Southwest Monsoon conditions that prevailed in September 2023 are expected to continue into the month of October. It is expected that during this period, the prevailing winds over the ASEAN region are blowing mostly from the southeast or southwest. Northern ASEAN region may experience rainy weather while drier conditions may be expected in the southern part of the region. Towards the end of October 2023, the weak or variable winds may be experienced as the inter-monsoon period sets in. Meanwhile, increased shower activities over most of the equatorial region may be expected as the monsoon rain-band migrates southwards towards the equator.

For the next 3 months, (October-November-December 2023), an increased chance of below-normal rainfall is predicted for most of the southern ASEAN region, extending to include the Philippines. Meanwhile, an increased chance of above-normal rainfall is also predicted over parts of Mainland Southeast Asia over this period. El Niño conditions are predicted to strengthen over the next few months and persist at least until the start of 2024 and a positive Indian Ocean Dipole (IOD) is now present and likely to persist during October-November. El Niño and positive IODs may bring drier conditions to most parts of the region. Above-normal temperature is predicted for most of the ASEAN region for October-November-December 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 : Jasmine Alviar, Sadhu Zukhruf Janottama, Lawrence Anthony Dimailig

GENERAL REVIEW OF JUNE 2023

For the month of June 2023, a total of 65 disasters were reported. The ASEAN Member States that were affected are Indonesia, the Philippines, and Viet Nam. Most of the disasters (66%) occurred in Indonesia but only accounted for 15% of the affected persons (around 78K persons). Notably, Philippines accounted for most of the affected persons despite reporting only 19 disasters events—Flooding in BARMM with 46.25% of the total reported affected persons for the month of June. The share of the disaster-affected people for the other ASEAN Member States are as follows: (1) Philippines-85.12%, (2) Indonesia-14.85%, and (3) Viet Nam-0.03%. June 2023 saw disasters affecting 77 per 100,000 people* and displacing 6 per 100,000 people* in the region, which were 4 times and 23 times lower respectively compared to the previous month.

Most of the disasters that have occurred in June 2023 are floods (45%) and is consistently the most recorded type of disaster for June of the previous year and June on a five-year average (2018-2022). The reported disasters in the region for June 2023 in comparison to the historical data (average for June 2018-2022) indicates that there were about 1.1x more reported disasters; 1.6x less people affected; 1.6x more people internally displaced; 2.3x less houses affected to some extent; 2.2x less lives lost; and 4.9x more people suffering injuries.

GENERAL REVIEW OF JULY 2023

For the month of July 2023, a total of 93 disasters were reported. The ASEAN Member States that were affected are Indonesia, Malaysia, Philippines, Thailand, and Viet Nam. Most of the disasters (72%) occurred in Indonesia but only accounted for 1.72% of the affected persons (around 101K persons). Notably, Philippines accounted for most of the affected persons despite reporting only 13 disasters event—Combined Effects of the Southwest Monsoon, TC DOKSURI, TC KHANUN, and TC TALIM with 94.29% of the total reported affected persons for the month of July. The share of the disaster-affected people for the other ASEAN Member States are as follows: (1) Philippines-98.016%, (2) Indonesia-1.723%, Thailand-0.238%, Viet Nam 0.022%, and Malaysia 0.001%. July 2023 saw disasters affecting 774 per 100,000 people* and displacing 76 per 100,000 people* in the region, which were 10 times and 4 times higher respectively compared to the previous month.

Most of the disasters that have occurred in July 2023 are floods (60%) and is consistently the most recorded type of disaster for July of the previous year and July on a five-year average (2018-2022). The reported disasters in the region for July 2023 in comparison to the historical data (average for July 2018-2022) indicates that there were about 1.5x more reported disasters; 3.2x more people affected; 1.5x less people internally displaced; 3.3x more houses affected to some extent; 1.2x more lives lost; and 1.5x more people suffering injuries.

GEOPHYSICAL CONDITION FOR JUNE AND JULY 2023

Geophysically, 48 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), and the Thai Meteorological Department (TMD) for the period of June to July 2023 (the period of Weeks 22-30).

Mount Semeru (Alert Level III), Anak Krakatau (Alert Level III), Dukono (Alert Level II), Ibu (Alert Level II), Ili Lewotolok (Alert Level II), and Karangetang (Alert Level III) 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 June to July 2023 (the period of Weeks 22-30).

PHIVOLCS raised the Mayon Volcano Alert Level to 3 (Increased Tendency Towards Hazardous Eruption) since 8 June. As of 14 August, 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 13 August 2023, 9.9K families (38.4K persons) have been affected and 20.3K persons internally displaced in 27 evacuation centres. The NDRRMC with other relevant-agencies/stakeholders have provided 5.7M USD worth of assistance to those affected.

*computed based on 2023 population data from worldometers.com

ANALYSIS

According to the ASEAN Specialised Meteorological Centre (ASMC), compared to the average value from 2001-2022, during June 2023, above-average rainfall was experienced in the eastern parts of the Mainland Southeast Asia and western Maritime Continent but less to above-average for the rest of the ASEAN Region. The largest difference (driest condition) from the average rainfall was observed over western coast to northern parts and southern Myanmar, western Thailand (bordering with southern parts of Myanmar), and the Visayas of the Philippines. Wetter conditions which is detected over Mindanao of the Philippines, have also resulted a MODERATE disaster in the area of BARMM Region. As shown in Figure 1 left wetter than normal conditions are detected over Mindanao, the Philippines.

For the month of July 2023, according to the ASMC, compared to the average value from 2001-2022, above-average rainfall was experienced over much of the western half of the maritime continent; below-average rainfall was experienced over the northeastern parts of the Mainland Southeast Asia and eastern Maritime Continent; and mix of below to above-average rainfall for the rest of the ASEAN Region. The largest positive (wetter) anomalies were recorded over parts of southern Myanmar, southern Viet Nam, and northern Philippines. Particularly for the wetter conditions in the northern parts of the Philippines as shown in Figure 2 left, a CATASTROPHIC disaster was caused by the Combined Effects of the Southwest Monsoon, TC DOKSURI, TC KHANUN, and TC TALIM.

SEASONAL OUTLOOK

According to the ASEAN Specialised Meteorological Centre (ASMC), compared to the average value from 2001-2022, during June 2023, above-average rainfall was experienced in the eastern parts of the Mainland Southeast Asia and western Maritime Continent but less to above-average for the rest of the ASEAN Region. The largest difference (driest condition) from the average rainfall was observed over western coast to northern parts and southern Myanmar, western Thailand (bordering with southern parts of Myanmar), and the Visayas of the Philippines. Wetter conditions which is detected over Mindanao of the Philippines, have also resulted a MODERATE disaster in the area of BARMM Region. As shown in Figure 1 left wetter than normal conditions are detected over Mindanao, the Philippines.

For the month of July 2023, according to the ASMC, compared to the average value from 2001-2022, above-average rainfall was experienced over much of the western half of the maritime continent; below-average rainfall was experienced over the northeastern parts of the Mainland Southeast Asia and eastern Maritime Continent; and mix of below to above-average rainfall for the rest of the ASEAN Region. The largest positive (wetter) anomalies were recorded over parts of southern Myanmar, southern Viet Nam, and northern Philippines. Particularly for the wetter conditions in the northern parts of the Philippines as shown in Figure 2 left, a CATASTROPHIC disaster was caused by the Combined Effects of the Southwest Monsoon, TC DOKSURI, TC KHANUN, and TC TALIM.

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 : Sadhu Zukhruf Janottama, Lawrence Anthony Dimailig

GENERAL REVIEW OF AUGUST 2023

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.

GEOPHYSICAL CONDITION FOR AUGUST 2023

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

ANALYSIS

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.

SEASONAL OUTLOOK

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

GENERAL REVIEW OF MAY 2023

For the month of May 2023, a total of 88 disasters were reported. The ASEAN Member States that were affected are Indonesia, Myanmar, the Philippines, Thailand, and Viet Nam. Most of the disasters (70%) occurred in Indonesia but only accounted for 8% of the affected persons (around 154,000). Notably, Myanmar accounted for most of the affected persons despite reporting only 1 disaster event—Tropical Cyclone MOCHA with 63% of the total reported affected persons for the month of May. The share of the disaster-affected people for the other ASEAN Member States are as follows: (1) Philippines-11%, (2) Thailand-18.12% and (3) Viet Nam-0.03%. May 2023 saw disasters affecting 284 per 100,000 people* and displacing 137 per 100,000 people* in the region, which were 3 times and 15 times higher respectively compared to the previous month.

Most of the disasters that have occurred in May 2023 are floods (51%) and is consistently the most recorded type of disaster for May of the previous year and May on a five-year average (2018-2022). The reported disasters in the region for May 2023 in comparison to the historical data (average for May 2018-2022) indicates that there were about 1.4x more reported disasters; 4.8x more people affected; 66x more people internally displaced; 7x more houses affected to some extent; 27x more lives lost; and 3.5x less people suffering injuries;.

Geophysically, 24 significant earthquakes (Magnitude ≥ 5.0) were reported by Indonesia’s Badan Meteorologi, Klimatologi dan Geofisika (BMKG), Thailand Meteorological Department (TMD), and the Philippine Institute for Volcanology and Seismology (PHIVOLCS).

Mount Semeru (Alert Level III), Anak Krakatau (Alert Level III), Ili Lewotolok (Alert Level II), Dukono (Alert Level II), and Ibu (Alert Level II) in Indonesia and Taal (Alert Level 2) and Kanlaon Volcanoes (Alert Level 1) were reportedly tectonically active (erupting lava or releasing gas or generating seismic activity) throughout the month of May 2023.

*computed based on 2023 population data from worldometers.com

ANALYSIS

According to the ASEAN Specialised Meteorological Centre (ASMC), compared to the average value from 2001-2022, during May 2023, less to near-average rainfall was experienced in Mainland Southeast Asia but more to near-average for the Maritime Continent. The largest difference (driest condition) from the average rainfall was observed over southern Myanmar and southern Thailand. Despite these dry conditions detected over Myanmar, a MAJOR disaster was caused by Tropical Cyclone MOCHA in its western and northwestern regions. As shown in Figure 1.a and 1.b, despite majorly exhibiting drier conditions, the areas within the track of cyclone MOCHA exhibited drier than normal conditions.

SEASONAL OUTLOOK

According to the ASEAN Specialised Meteorological Centre (ASMC), Southwest Monsoon conditions are expected to be established from June 2023 and persist until August 2023. These conditions traditionally bring rain often resulting in widespread and persistent shower activities in the northern ASEAN region. Over the southern ASEAN region, the Southwest Monsoon seasons is characterised by drier conditions compared to other times of the year, as the monsoon rain band typically lies further north from the Equator.

For the next 3 months, (June-July-August 2023), an increased chance of below-normal rainfall is predicted for much of the southern ASEAN region, with highest likelihood over the southern Maritime Continent. ENSO neutral conditions are present but will likely transition into El Nino in the next few months. Warmer-than-normal temperature is predicted for much of the ASEAN region.

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

GENERAL REVIEW OF SEPTEMBER 2022

For the month of September 2022, a total of 193 disasters or a daily average of 6 disasters were reported. Compared to the previous month (August), this is more than twice as many and 1.5x higher compared to September of the previous year. This is also 3.4x higher than the five-year average (2017-2021) of disaster occurrences for the month of September. September 2022 saw disasters affecting 596 per 100,000 people* and internally displacing 10 per 100,000 people*. From the start of the year 2022, a total of 11.6M persons have been affected by disasters or an average of 42,591 persons in a day. This total is already 1.2M or 11% higher than the same period of the previous year.

The ASEAN Member States that were affected are Cambodia, Indonesia, Malaysia, the Philippines, Thailand, and Viet Nam. Most of the disasters (68%) occurred in Indonesia but only accounted for 8% of the total reported affected persons for September 2022. Thailand, despite accounting for only 6% of the disaster occurrences for the month, accounted for 73% (2,916,745) of the total reported affected persons for the month. On one hand, the share of disaster occurrences for the other member states are as follows: Cambodia – 3%, Malaysia – 3%, The Philippines 8%, and Viet Nam – 10%. On the other hand, the share of affected persons for the other member states are as follows: Cambodia – 0.001%, Malaysia – 0.0004%, the Philippines – 37%, and Viet Nam – 1.6%.

Most of the disasters that have occurred in September 2022 are floods (63%) and is consistently the most recorded disaster-causing natural hazard for September of the previous year and September on a five-year average (2017-2021). The reported disasters in the region for September 2022 in comparison to the historical data (average for September 2017-2021) indicates that there were about 3.4x more reported disasters; 1.08x less people affected; 2.4x less people internally displaced; 9.8x more houses affected to some extent; 8.5x less lives lost; 12x less people suffering injuries; and lastly, 28x less people that have gone missing. The main drivers of the impacts in the ASEAN region were the monsoon situation in Thailand that have caused widespread flooding as reported by the Department of Disaster Prevention and Mitigation (DDPM) and the impacts of Tropical Cyclone (TC) NORU in the Philippines, Viet Nam, Lao PDR, Cambodia, and Thailand. The tropical cyclone affected multiple member states, but the Philippines’ resources were sufficient, and Viet Nam was able to prepare well. Thailand had requested for relief items in response to TC NORU-associated flooding which has worsened the situation in areas that have long been impacted by the monsoon situation.

Geophysically, 43 significant earthquakes (Magnitude ≥ 5.0) were reported by Indonesia’s Badan Meteorologi, Klimatologi dan Geofisika (BMKG), the Philippine Institute for Volcanology and Seismology (PHIVOLCS), the Thai Meteorological Department (TMD), and the Department of Meteorology and Hydrology (DMH) of Myanmar. This emphasizes the importance of disaster preparedness as three ASEAN Member States lie on the “Pacific Ring of Fire,” a zone of active volcanoes and frequent earthquakes.

Mount Semeru, Ili Lewotolok (Alert Level III), and Ibu, Dukono (Alert Level II) in Indonesia and Taal Volcano (lowered to Alert Level 1), Mayon, Mount Kanlaon (Alert Level 1) were reportedly tectonically active (erupting lava or releasing gas or generating seismic activity) throughout the whole of September 2022.

*Computed based on 2020 population data from worldometers.com

SEASONAL OUTLOOK

For the month of September 2022, much of the ASEAN region experienced rainfall more than what is traditionally experienced for the month. Wetter conditions (compared to the average for September 2022) were recorded over Viet Nam and Southern Borneo hence the hydrometeorological-induced disasters in Viet Nam and Indonesia. In contrast, below-average to average rainfall were recorded in Peninsular Malaysia, the Philippines, and Northern Myanmar, northern Lao PDR, northern Sumatra and northern Papua of Indonesia. Despite this, hdyrometeorological hazard-induced disasters still occurred in most of these areas (except northern Myanmar, northern Lao PDR, and northern Papua).

According to the ASEAN Specialised Meteorological Centre (ASMC), for the October-November-December period much of the ASEAN region will be experiencing above-normal rainfall. Normally, this period is regarded as the disaster season for the region. This is on top of the traditionally wet monsoon seasons in Thailand (May-October), Cambodia (May-October), Lao PDR (May-October), Viet Nam (May-November), the typhoon season in the Philippines (July-October) and the start of the rainy season in Indonesia (November-March). Therefore, the threat of hdyrometeorological hazard-induced disasters is even more likely.

In terms of temperature, below- to near-normal temperatures are favoured for parts of the equatorial region and much of the Mainland Southeast Asia, with above-normal temperature favoured elsewhere which likely means for hotspot activities to generally be subdued for the period.

The qualitative outlook is assessed for the region in general. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted. More outlook and verification plots, including for tercile and quintile probabilistic forecasts for temperature, are in the “Model products and verification: NCEP, ECMWF, UK Met Office” on the SEA-RCC Network LRF Node webpages.

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, National Disaster Risk Reduction and Management Council (NDRRMC) – Philippines, Department of Disaster Prevention and Mitigation (DDPM) – Thailand, Thai Meteorological Department (TMD) – TMD, 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

GENERAL REVIEW OF DECEMBER 2021

For the month of December 2021, a total of 204 disasters were reported. The ASEAN Member States that were affected are Indonesia, Malaysia, Myanmar, the Philippines, Thailand, and Viet Nam. Most of the disasters (88.73%) occurred in Indonesia but the highest number of affected people were reported for the Philippines at more than 8 million. The number of affected persons from the Philippines comprised the majority of the tally for the month of December (87.36%) and is attributed with the developments of Tropical Cyclone RAI. The share of the disaster-affected people for the other ASEAN Member States are as follows: (1) Indonesia-8.6%, (2) Malaysia-0.71%, (3) Myanmar-0.001%, (4) Thailand-0.15%, and (5) Viet Nam-%. December 2021 saw disasters affecting 1,410 per 100,000 people* and displacing 117 per 100,000 people* in the region, which were 8 times and 28 times higher respectively compared with the previous month. December 2021 accounts for 14.51% of the total disasters (1,406), 71.69% of the total cost of damages (814.8 Million USD), and 69.83% of the total cost of assistance provided (21.1 Million USD) reported so far in the current year.

Most of the disasters that have occurred in December 2021 are floods (74.02%) and is consistently the most recorded type of disaster for December of the previous year and December on a five-year average (2016-2020). December 2021 saw disasters caused by hydrometeorological hazards (flood, rain-induced landslides, storm, winds) affecting 99.68% of the total affected persons for the month. The reported disasters in the region for December 2021 in comparison to the historical data (average for December 2016-2020) indicates that there were 7.5x more reported disasters; 3.4x more people affected; 4.6x more people displaced; 15.7x more houses affected to some extent; 5.8x more lives lost; 16.2x more people suffering injuries; and lastly, 10.5x more people that have gone missing.

*Computed based on 2020 population data from worldometers.com

ANALYSIS

According to the ASEAN Specialised Meteorological Centre (ASMC), compared to the average value from 2001-2020, during December 2021, rainfall was above-average over coastal central parts of Viet Nam, Peninsular Malaysia, and the southern half of the Philippines. The largest positive anomalies (wetter conditions) were detected over central Philippines and Peninsular Malaysia (due to Super Typhoon RAI and Tropical Depression 29W respectively, which made landfall in mid-December), for both satellite-derived rainfall estimates datasets (GSMaP-NRT and CMORPH-Blended). As expected, the start of the dry season for the northern ASEAN region resulted in negligible rainfall anomalies for the rest of Mainland Southeast Asia, where only four disasters caused by floods were reported. Meanwhile, for the equatorial ASEAN region, a mix of above- and below-average rainfalls were observed and accordingly, a number of hydrometeorological disasters were reported.

SEASONAL OUTLOOK

In the month of December 2021, the Northeast Monsoon was established over a majority of the ASEAN region and is expected to persist until late March 2022. It is during this period that inter-monsoon conditions will typically start to develop. Climatologically, the northern ASEAN region experiences its traditional dry season during the period with the prevailing low-level winds blowing from the northeast or east. Wet conditions will typically prevail over the southern ASEAN region as the monsoon rain band progresses south of the equator. This is seen to occur during the beginning of the outlook period before becoming drier and occasionally windy. This happens as the region experiences the dry phase of the Northeast Monsoon starting late January to early March. The prevailing low-level winds over the southern ASEAN region are expected to blow from the north or northwest. Hydrometeorological disasters are likely as the monsoon rain band moves towards the south of the equator and are less likely for the northern ASEAN region and the southern ASEAN region in the coming weeks during the transition into the dry phase of the Northeast Monsoon.

In the coming period (January to March 2022), there is an increased chance of above-normal rainfall over eastern parts of the Maritime Continent and the Malay Peninsula. La Niña conditions are present. Models are predicting weak to moderate La Niña conditions until March-April 2022, after which the conditions are predicted to return to neutral during April-June 2022. Warmer-than-usual temperature is expected for much of the Maritime Continent (except the Malay Peninsula where near-normal temperature is predicted) and Myanmar during JFM 2022.

Hotspot activities and smoke haze situation are seen to intensify especially in northern parts of Myanmar as the traditional dry season over the northern ASEAN region progresses. Subdued hotspot activities are expected in the southern ASEAN region due to the current wet conditions, but localised hotspots can still occur occasionally during the transition to the dry phase of the Northeast Monsoon.

*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

GENERAL REVIEW OF NOVEMBER 2021

For the month of November 2021, a total of 145 disasters were reported. The ASEAN Member States that were affected are Indonesia, Malaysia, the Philippines, Thailand, and Viet Nam. Most of the disasters (84.14%) occurred in Indonesia and the highest number of affected people were also reported in Indonesia which comprise more than half of the tally for the month of November (54.45%). The share of the disaster-affected people for other ASEAN Member States are as follows: (1) Malaysia-0.20%, (2) the Philippines-1.19%, (3) Thailand-42.72%, and (4) Viet Nam-1.45%. November 2021 saw disasters affecting 144 per 100,000 people* and displacing 4 per 100,000 people* in the region, recording a 57.11% and a 77.23% lower numbers respectively compared with the previous month. November 2021 accounts for 12.06% of the total disasters (1,202) reported so far in the current year.

Most of the disasters that have occurred in November 2021 are floods (83.45%) and is consistently the most recorded type of disaster for November of the previous year and November on a five-year average (2016-2020). November 2021 saw disasters caused by hydrometeorological hazards (flood, landslides, storm, winds) affecting 99.31% of the total affected persons for the month. The reported disasters in the region for November 2021 in comparison to the historical data (average for November 2016-2020) indicates that there were 6x more reported disasters; 2.21x less people affected; 5.62x less people displaced; 1.15x more houses affected to some extent; 4.87x less lives lost; 14.06x less people suffering injuries; and lastly, 1.36x less people that have gone missing.

Geophysically, 20 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). In Central Maluku Indonesia, a Magnitude 5.9 earthquake affected 210 people, displaced 6 people and damaged 42 houses, 1 school, and 2 worship places. Recent volcanic activity was reported for Ili Lewotolok (Alert Level III) and Semeru, Ibu, Dukono (Alert Level II) in Indonesia, and Taal (Alert Level 2) and Kanlaon (Alert Level 1) in the Philippines.

*Computed based on 2020 population data from worldometers.com

ANALYSIS

According to the ASEAN Specialised Meteorological Centre (ASMC), compared to the average value from 2001-2020, during November 2021, rainfall was near-average over much Mainland Southeast Asia, above-average rainfall over southern Mainland Southeast Asia and a mix of below- to above-average for the Maritime Continent (Figure 1). The largest positive anomalies (wetter conditions) were detected over the southern Mainland Southeast Asia for both satellite-derived rainfall estimates datasets (GSMaP-NRT and CMORPH-Blended). This is resulted to flooding in Southern and Western Region of Thailand which is affected 70.8K families (353.9K people) and cost the lives of 2 individuals. Negative anomalies (drier conditions) were recorded over central Sumatra and the Philippines, with larger negative anomalies based on CMORPH-Blended data compared to GSMaP-NRT.

SEASONAL OUTLOOK

From the second half of the month of October 2021, the Southwest Monsoon had transitioned into the inter-monsoon period. On a climatological standpoint, inter-monsoon conditions likely prevails over the ASEAN region in November before the Northeast Monsoon conditions develop in December. Inter-monsoon conditions are characteristic of light and variable in direction prevailing winds. In terms of precipitation, the monsoon rain band will be located closer to the equator hence an increase in rainfall over the equatorial ASEAN region can be expected.

In the coming period (December 2021 to February 2022), there is an increased chance of near- to above-normal rainfall over much of the Maritime Continent , and a mix of below- to above-normal rainfall over Mainland Southeast Asia with the above-normal rainfall possibly pertaining to chances of hydrometeorological disasters occurring. La Niña conditions are present and models are predicting weak to moderate La Niña conditions until March-April, after which the conditions are predicted to weaken. The negative Indian Ocean Dipole (IOD) event has ended and is expected to be neutral for the coming months. Warmer-than-usual temperature is expected for much of the Maritime Continent and Myanmar during the period of December 2021 to February 2022.

The dry season over the southern ASEAN region had ended in mid-October 2021. In the northern ASEAN region, the traditional dry season typically sets in at the end of the year. While there is an increased chance of above-normal rainfall over some parts of the northern ASEAN region, hotspot and smoke haze activity can still be expected to progressively intensify over the fire-prone areas in the Mekong sub-region, with an increased likelihood of transboundary haze occurrence during this period.

*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

GENERAL REVIEW OF OCTOBER 2021

For the month of October 2021, a total of 144 disasters were reported. The ASEAN Member States that were affected were Cambodia, Indonesia, Malaysia, the Philippines, Thailand and Viet Nam. Most of the disasters (54.86%) occurred in Indonesia but the highest number of affected people was reported in the Philippines which comprised more than half of the tally for the month of October (55%). The share of the disaster-affected people for other ASEAN Member States was as follows: (1) Cambodia-0.66%, (2) Indonesia-25.40%, (3) Malaysia-0.08%, (4) Thailand-15.89%, and (5) Viet Nam-2.97%. October 2021 saw disasters affecting 335 per 100,000 people* and displacing 11 per 100,000 people* in the region, recording a 22.63% decrease and a 35.29% respectively, from the previous month. October 2021 accounts for 13.64% of the total disasters (1,056) reported so far in the current year.

Most of the disasters that occurred in October 2021 were floods (62.5%) and this is consistently the most recorded type of disaster for October of the previous year and October on a five-year average (2016-2020). October 2021 saw hydrometeorological disasters (droughts, floods, rain-induced landslides, storms, winds) affecting 99.6% of the total affected persons for the month. The reported disasters in the region for October 2021 in comparison with the historical data (average for October 2016-2020) indicates that there were 8x more reported disasters; 1.34x fewer people affected; 1.22x fewer people displaced; 1.97x more houses affected to some extent; 6.58x fewer lives lost; 22.47x fewer people suffering injuries; and lastly, 14.05x fewer people reported missing.

Geophysically, 18 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). In Bali Indonesia, a magnitude 4.8 earthquake, albeit not a significant earthquake, affected 7,690 people and damaged 2,320 houses. Recent volcanic activity was reported for Ili Lewotolok (Alert Level III) and Semeru, Kerinci, Ibu, Karangetang, Krakatau (Alert Level II) in Indonesia, and Taal (Alert Level 2) and Kanlaon (Alert Level 1) in the Philippines.

*Computed based on 2020 population data from worldometers.com

ANALYSIS

According to the ASEAN Specialised Meteorological Centre (ASMC), compared with the average value from 2001-2020, during October 2021, rainfall was above-average over much of the northern ASEAN region and a mix of below- to above-average for the southern ASEAN region (Figure 1). The largest positive anomalies (wetter conditions) were detected over the eastern Mainland Southeast Asia for both satellite-derived rainfall estimates datasets (GSMaP-NRT and CMORPH-Blended). This is associated with the developments of Severe Tropical Storm KOMPASU. A second tropical storm, Tropical Storm LIONROCK, affected central Philippines at the beginning of October, which is the major reason for the positive anomalies in central Philippines and the ocean region around the Philippines. Negative anomalies (drier conditions) were recorded over western and northern parts of Borneo. For the rest of the ASEAN region, rainfall tended to be near-to above-average during October 2021.

SEASONAL OUTLOOK

In the second half of October 2021, according to the ASMC, the Southwest Monsoon had transitioned into the inter-monsoon period. Climatologically, the inter-monsoon conditions are likely to prevail over the ASEAN region in the coming month of November as the conditions transition into the Northeast Monsoon by December. During this inter-monsoon period, prevailing winds are forecast to be generally light and variable in direction. Increased rainfall is expected, particularly over the areas of the ASEAN region near the equator, due to the equatorial proximity of the monsoon rain band.

In the coming three months (November 2021 to January 2022), the Maritime Continent and southeastern Mainland Southeast Asia are looking at an increased chance of above-normal rainfall. The areas with the highest chances are southern and eastern parts of the Maritime Continent. La Niña conditions have been detected and are now present according to the ASMC. This entails wetter-than-average rainfall conditions and cooler conditions in the region. Additionally, most models are predicting these conditions to last or be experienced until early 2022. As the month of October ended, a negative Indian Ocean Dipole (IOD) that brought greater precipitation east of the Indian Ocean was present and this negative IOD was expected to return to neutral in the month of November 2021 (positive IOD causes droughts in Southeast Asia). Temperatures that are warmer than usual are likely for much of the Maritime Continent and Myanmar in the coming three months (November 2021-January 2022).

The dry season over the southern ASEAN region ended in October 2021. Meanwhile, for the northern ASEAN region, the traditional dry season typically sets in by year-end.
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.

*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

GENERAL REVIEW OF SEPTEMBER 2021

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

ANALYSIS

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.

SEASONAL OUTLOOK

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