GENERAL OVERVIEW OF JULY 2019

During the month of July 2019, as many as 27 disasters were reported within the region. This figure is 29% higher than the previous five-year average number of disaster occurrences for July – with an observable spike in the number of earthquake and landslide occurrences. However, all other figures are lower than the respective five-year average, except for numbers of injured persons. The number of injured people increased by 64% due to the M7.2 earthquake that struck North Maluku during the second week of July. In general, the lower disaster impact figures for July this year, in comparison to the average during the last five years, can be attributed primarily to the magnitude of disaster occurrences. In July 2014, Typhoon Ramassun battered the Philippines and Viet Nam, Myanmar was heavily flooded in 2015, and drought significantly impacted Myanmar and the Philippines during 2018. These major disaster events affected between 1.7 million to 4.5 million people, displaced hundreds of thousands, and resulted in mass casualties. This year, only minor and moderate disaster events have occurred, resulting in only impact numbers of 32% of the five-year average affected people, and 10% of the five-year average internally displaced people.

There were 46 earthquakes of at least magnitude 5.0 recorded in Indonesia and the Philippines during the month. July 2019 was characterised by quite a number of earthquake events that resulted in minor to significant damages. Collectively, these earthquake events contributed to at least 79% in this month’s casualties (dead, injured, and missing), had a 65% share in causing internal displacement, and caused 92% of damaged houses.

SEASONAL OUTLOOK

Rainfall data for the month of July 2019 indicates near to above normal rainfall conditions were experienced in Lao PDR, Myanmar, Singapore, Thailand, Viet Nam, and most parts of Malaysia, the Philippines, and West Papua in Indonesia. Meanwhile, below normal rainfall conditions were recorded over eastern Indonesia and portions of southern Malaysia. Similar conditions are expected to persist as the impact of Southwest Monsoon continues in the region. For the next three months, the ASEAN Specialised Meteorological Centre (ASMC) expects generally above-normal rainfall conditions in the southern parts of Cambodia, Myanmar, Thailand, and Viet Nam, while generally below-normal rainfall conditions are predicted over the southern ASEAN region and over southern Philippines. In addition, the Indian Ocean Dipole (IOD) is currently showing positive values, and is expected to persist into the 3rd quarter of 2019. A positive IOD can lead to below-normal rainfall conditions over Singapore and nearby areas, which will contribute further to the current drier conditions. Coupled with the effects of the Southwest Monsoon, there is a potential for an escalation of hotspot activities in the southern ASEAN region, which may lead to an increase in the risk of transboundary haze occurrence.

The potential for recurrence of flooding in the Mekong sub-region, and the continuation of drought in the southern ASEAN region, requires readiness in terms of monitoring and response. In line with this, the AHA Centre joined the National Disaster Risk Reduction and Management Council, the Office of Civil Defense, and the Pacific Disaster Center during the launch of PhilAWARE and National Disaster Preparedness Baseline Assessment in the Philippines. These initiatives aim to increase preparedness capacities of the Philippines, including monitoring hazards within its jurisdiction. In addition, the AHA Centre also conducted the Pilot ASEAN Humanitarian Civil-Military Coordination Course, and participated in the ASEAN Defence Ministers Meeting (ADMM) Plus Humanitarian Assistance and Disaster Response Communications and Staff Exercises. These events contribute to the readiness of the Centre in coordinating military assistance during emergency response.

Data Sources: ASEAN Disaster Information Network, ASEAN Specialised Meteorological Centre

Written by : Lawrence Anthony Dimailig & Shahasrakiranna

GENERAL OVERVIEW OF JUNE 2019

Disaster occurrences in June 2019 amounted to only half of the average for June across the previous five years. Interestingly, while the impact of Southwest Monsoon in the region brings traditionally wet conditions in most ASEAN Member States, during this month the numbers of flooding, storms, and wind-related disturbances recorded were significantly less than those of the previous five years. Meanwhile, reported drought incidents rose significantly when compared with the last five years. These conditions may have been influenced by the borderline El Niño currently being experienced in the region, which resulted to lower-than-normal rainfall and higher-than-normal temperature. On the other hand, it is also important not to discount the possibility that the increase in drought reports may be due to developments in drought monitoring and reporting processes and technology across the region.

While the number of disaster occurrences are significantly lower than the previous five-year average, the number of reported affected people remained similar at 86%. This suggests that disaster occurrences in June 2019 had a higher impact than many incidents across the past five years. In addition, the reported number of internally displaced people (IDP) is 2.5 times higher than the previous five-year average. The high number of IDPs was driven by the reported sudden change of atmospheric conditions in the southern Philippines, which experienced continuous heavy rains after being devastated by drought for weeks. On the other hand, damaged houses and casualties recorded significantly lower numbers than the previous five-year average, which may be attributable to decreased flooding and rain-induced landslides – key drivers of high numbers of damaged houses and casualties, in addition to earthquakes. June 2019 recorded 32 earthquakes of magnitude 5.0 and above, and while there was one earthquake in Indonesia that affected people and damaged houses, the impact was still considered minor.

SEASONAL OUTLOOK

The ASEAN Specialised Meteorological Centre (ASMC) predicts the prevailing Southwest Monsoon to continue until October 2019. As a result, general continuity of rainy conditions in the northern ASEAN region and dry conditions in the southern ASEAN region can be expected. In addition, above-normal rainfall is forecast in several parts of Cambodia, Myanmar, Thailand and Viet Nam, while above-normal temperatures are likely in most parts of the region except for southern parts of ASEAN. The El Niño Southern Oscillation monitoring system remains in the “Watch” status for the region, which suggests borderline El Niño conditions. Looking forward, overall signs of future El Niño development have weakened, however, model outlooks of international centres still show a wide spread of outcomes ranging from neutral conditions to moderate El Niño.

Data Sources: ASEAN Disaster Information Network, ASEAN Specialised Meteorological Centre

Written by : Lawrence Anthony Dimailig & Shahasrakiranna

GENERAL OVERVIEW OF MAY 2019

Only four disaster occurrences were recorded in the ASEAN region during the month of May 2019 – all of which are hydro-meteo-climatological in nature. While the number of disaster occurrences registered was only around 27% compared to May’s previous five-year average, the number of reported affected people and damaged houses, were significantly above average, as much as 8 and 17 times respectively. The results are due to the drought and other related effects of El Niño in the Philippines (for affected people), and the combination of several atmospheric disturbances that brought storms and a rain-induced landslide in Thailand (for damaged houses). The geographic extent of drought conditions saw widespread impact in the Philippines, with 10 of the 17 regions in the country reported to have been affected. This formed a key driver for high numbers of affected people. In the case of Thailand, heavy rainfall conditions throughout the country were influenced by the strengthening of the Southwest Monsoon, coupled by multiple low pressure cells. This resulted in continuous heavy rainfall which eventually overwhelmed soil water absorption capacity, thereby resulting in rain-induced landslides. The combination of storms and rain-induced landslides resulted in higher numbers of damaged houses.

Generally, there were no fatalities or significant damages directly caused by geophysical hazards during the month. Nineteen earthquakes of magnitude 5.0 and above were recorded in Indonesia, Myanmar, and the Philippines, while four volcanoes in Indonesia are still under increased monitoring. In addition, an eruption at Mt. Agung in Indonesia was reported during the month, with several areas affected by ash rain. Fortunately, most of the population are located outside the hazard zones, and hence no evacuations were triggered.

SEASONAL OUTLOOK

The Southwest Monsoon is normally experienced by the ASEAN region during June. Traditionally, Southwest Monsoon results in the rainy season through the northern part of the region, while the southern parts experience a dry period. Meanwhile, the ASEAN Specialised Meteorological Centre expects the borderline El Niño conditions in the region, which have been observed since the last quarter of 2018, to continue until August 2019. Also, the Indian Ocean Dipole is expected to develop into its positive state, with lower than average sea surface temperatures. As a result, while rainy conditions are expected across most of the region, the amount of rainfall may potentially be below normal levels. There are, however, several areas that may experience wetter-than-normal conditions – specifically, Western and Southern Myanmar, and parts of Sumatra, Northern Sulawesi, Moluccas, and Papua in Indonesia. Finally, above-normal temperatures are expected in most of Central and Eastern Southeast Asia, including parts of Peninsular Malaysia, Singapore, and Central and Western Indonesia during the next 3 months.

As the Southwest Monsoon is predicted to be in full effect throughout the region across the next few weeks, the occurrence of tropical cyclones over the Bay of Bengal and Western Pacific are expected. This puts the Mekong sub-region and the Philippines at-risk. To support such anticipated events, the AHA Centre is finalising its preparations for the launch of the Disaster Emergency Logistics System for ASEAN (DELSA) Satellite Warehouses in the Philippines and in Thailand, that aims to improve the delivery of relief resources to Member States. For longer-term impact, the AHA Centre, in partnership with the Pacific Disaster Center, aims to gain a deeper understanding of disaster risk of countries in the ASEAN region through the National Disaster Preparedness Baseline Assessment (NDPBA). With a more detailed assessment, the NDPBA is expected to identify specific risk elements for increased investment focus, in order to increase resilience. The NDPBA has been launched in Viet Nam, and has scheduled upcoming launches in Indonesia and the Philippines. Lastly, the AHA Centre will explore a new concept in Disaster Risk Reduction through the upcoming 3rd Asia Pacific Dialogue Platform on Forecast-based Financing (FbF). FbF is a programme that enables access to humanitarian funding for early action based on in-depth forecast information and risk analysis. The goal of FbF is to anticipate disasters, prevent their impact if possible, and reduce impact on human populations.

Data Sources: ASEAN Disaster Information Network, ASEAN Specialised Meteorological Centre

Written by : Lawrence Anthony Dimailig & Shahasrakiranna

GENERAL OVERVIEW OF APRIL 2019

April began 2019’s second quarter by continuing the trend of lower disaster occurrences compared to the average of the five previous years, with the number of people affected by disaster reaching only 11% of the previous five-year average. This significant difference is primarily caused by an extreme event during 2016 that skews the five-year average – namely the 2016 drought in Cambodia that affected 2.5 million people. On the other hand, April 2019 witnessed higher-than-average displacement, house damage, and casualty figures. A majority of population displacement during April was due to widespread flooding and rain-induced landslides in Indonesia and Myanmar. Increased atmospheric activity, due to the inter-monsoon period, resulted in scattered rain showers across the region, while the Madden-Julian Oscillation further enhanced the duration and amount of rainfall in Indonesia during the last week of the month. Meanwhile, a majority of house damage was due to a hailstorm in Central Myanmar, that saw hailstones as large as golf balls raining down on homes made from light materials. Three disaster events significantly influenced the rise in casualties across the region – namely flooding, followed by a rain-induced landslide in Bengkulu Province, Indonesia, and the magnitude 6.1 earthquake in Central Luzon, the Philippines.

Geophysical activity registered 56 earthquakes of magnitude 5.0 and above during April 2019. Three of these earthquakes resulted in significant impact to people and structures, seeing them classified in disaster statistics – a 6.8M in Central Sulawesi, Indonesia (close to ground zero for the devastating 7.5M earthquake that triggered a tsunami and liquefaction in 2018), and back-to-back 6.1M and 6.5M earthquakes in Central Luzon and Eastern Samar, the Philippines. Lastly, there were four volcanoes, all in Indonesia, being monitored due to increased activities – Mount Agung, Mount Karangetang, and Mount Soputan, all at Alert Level 3, and Mount Sinabung, which is at Alert Level 4, the highest alert level for volcanoes in Indonesia.

SEASONAL OUTLOOK

The inter-monsoon period is expected to last until June, upon which the Southwest Monsoon will become dominant in the region. During this transition, a northward shift of monsoon rain bands will be observed. While rainy conditions are expected in the northern ASEAN region, the ASEAN Specialised Meteorological Centre forecasts generally below-average rainfall. However, the gradual increase in rain shower activities is expected to subdue hotspot activities and improve haze conditions in the Mekong sub-region. Meanwhile, drier weather conditions are expected to slowly increase across the southern ASEAN region, particularly in Indonesia. Seasonal models tend to exempt the southern ASEAN region from the warmer temperatures expected in most of the region during the second quarter of the year.

As part of its preparatory activities for the rainy season in the northern ASEAN region and dry conditions in the southern ASEAN region, the AHA Centre will conduct a table-top exercise to test its Emergency Response Organisation procedures for responding to any disaster within the region. Alongside this, connectivity testing with respective Emergency Operations Centres (EOC) of each ASEAN Member State is also being planned. Finally, in cooperation with the Pacific Disaster Center (PDC Global), a DisasterAWARE Multi-Hazard Monitoring Platform is planned to be established in Brunei Darussalam, Cambodia, Lao PDR, and the Philippines. DisasterAWARE is a powerful and reliable early warning and multi-hazard monitoring platform, that supports disaster management and emergency response by providing early warning, multi-hazard monitoring, impact assessment modelling, and geospatial data. The Centre has been using the regionally-adapted version of DisasterAWARE, (Disaster Monitoring and Response System – DMRS), in its daily operations for many years. At present, the AHA Centre and PDC Global are working with Myanmar to develop capacity and capability to utilise the DMRS, while several ASEAN Member States already utilise their own versions of DisasterAWARE – including Indonesia, Thailand, and Viet Nam.

Data Sources: ASEAN Disaster Information Network, ASEAN Specialised Meteorological Centre

Written by : Lawrence Anthony Dimailig, Shahasrakiranna

GENERAL OVERVIEW OF MARCH 2019

March ended the first quarter of 2019 continuing the trend of lower disaster occurrences compared to its five-year average. This month registered 61% of its five-year average number of disaster occurrences, similar to the statistics of January 2019. However, the number of affected persons was more than 10 times the average for March, and the number of casualties is more than 13 times more than the previous 5 years on average. These considerable differences were driven by two significant events – the drought in North Cotabato, Philippines and the flooding in Sentani, Indonesia. 60% of this month’s affected population is attributed to the Philippines drought, particularly due to the drought’s extensive geographic coverage. On the other hand, 92% of this month’s casualties resulted from the flooding and landslide in Sentani, Indonesia. The primary factor for these figures can be attributed to the timing of the flash flood, which happened at night while most of the residents were sleeping in their homes. This highlights the importance of availability, accessibility, and utilisation of early warning information to drive early action.

Geophysical disasters decreased in March compared to the previous 2 months, with only 23 earthquakes of magnitude 5.0 and above recorded in the region. Of these recorded earthquakes, only one resulted in loss of life. A shallow earthquake with magnitude 5.4 struck north of Selong City in East Lombok Regency, Indonesia. This resulted in damage and collapse of structures in the area, as well as falling rocks and debris at the nearby Tiu Kelep Waterfall in North Lombok Regency, which resulted in the deaths of two tourists visiting the site. This highlights the nature and need for multi-disciplinary and cross-cutting approaches in disaster management

SEASONAL OUTLOOK

The ASEAN Specialised Meteorological Centre reports the end of the Northeast Monsoon, and that onset of the inter-monsoon period is taking place. This is the transition phase between the Northeast and Southwest Monsoons, which is characterised by increased occurrence of scattered rain showers in the region. While seasonal forecast models point to a general increase in rainfall frequency, and a geographic expansion of rain showers, precipitation on the other hand ranges from normal in the Philippines to below-normal in eastern Indonesia and the northern ASEAN region. While the amount of rainfall may not be considerably large, the increase in exposure may still trigger flooding and rain-induced landslides.

Statistically, large-scale disasters that require regional-level response occur during the second half of the year. At the end of 2019’s first quarter, the AHA Centre is wrapping up its preparatory activities for emergency response and other events. This includes the updating and preparation of Common Operational Datasets, 11th ASEAN-ERAT Induction Course, the preparation for the launch of the DELSA satellite warehouses and many more. Activities such as these help prepare the AHA Centre, and the region, to respond to disaster whenever and wherever it may strike.

Data Sources: ASEAN Disaster Information Network, ASEAN Specialised Meteorological Centre

Written by : Lawrence Anthony Dimailig

GENERAL OVERVIEW OF FEBRUARY 2019

February 2019 was characterised by an unusually low number of recorded disaster events, registering less than a quarter of the five-year average of occurrences for the month. Although the region experienced scattered rain showers in the south, and generally dry and hazy conditions in the north, the record-breaking low number of impact on communities (only 6% and 1% of the five-year average number for affected and displaced people respectively) could reflect the improving effectiveness of disaster management practices among ASEAN Member States. On the other hand, the recorded number of damaged houses was more than five times the five-year average. An overwhelming majority of the damage was caused by hailstorms and strong winds in Northeastern Viet Nam. Fortunately, about 84% (or 3,436) houses incurred only minor damage. In general, February 2019 was a more settled month for disaster managers across the region.

In addition to Indonesia’s South Solok Regency earthquake that resulted to minor damages, there were 30 other earthquakes of magnitude 5.0 and above in Indonesia and the Philippines during February. While still a high number, it forms only 48% compared to last month’s seismic activities of the same strength. There was also intensified dynamicity in volcanic activities in the region, most notably in Indonesia. Fortunately, only Mt. Karangetang (on Siau Island) experienced damage, which was also considered minor. This result is influenced by the increasing awareness of both authorities and communities to volcano-related risks, and their improved cooperation to mitigate and prevent impacts and damages.

SEASONAL OUTLOOK

The ASEAN Specialised Meteorological Centre reported that the prevailing Northeastern Monsoon season is expected to transition into the inter-monsoon period by the end of March 2019. During the inter-monsoon period, the region is expected to experience an increase in rain activity. This is good news for the Mekong sub-region, as it will help ease transboundary smoke haze in the area. However, this could also mean flooding, rain-induced landslides, and other hydrological hazards in the equatorial and southern parts of the ASEAN region – particularly in Indonesia and Malaysia. There remains a likelihood that the hotspots and smoke haze conditions in the Mekong sub-region could persist, however, it is expected that the prevailing dry season in northern ASEAN will gradually come to an end by April 2019.

With the expected increase in hydro-meteorological activities within the region, the AHA Centre is preparing by strengthening efforts to share early-warning information, and monitoring data and information between the Centre and National Disaster Management Organisations (NDMOs). This is being undertaken through conducting an ASEAN Workshop on Disaster Reporting and Big Data for Disaster Management, and the development of the proposed AHA Centre Information Management Technical Working Group (AIM-TWG). The workshop aims to build regional and national capacity in utilising current and new information and communication technologies, while AIM-TWG is envisioned to be a platform for cooperation and collaboration between and among AHA Centre and NDMOs for strengthening regional and national disaster information management capacities, capabilities, and practices.

Written by : Eviana Rosida, Lawrence Anthony Dimailig

GENERAL OVERVIEW OF DECEMBER 2018

As generally expected for the “winter” or Northeast monsoon period, the southern part of ASEAN – particularly Indonesia, Malaysia, southern Philippines and Thailand – experienced an increase in floods during December 2018. Some areas within those countries also experienced landslides due to heavy rainfall in mountainous areas.

In terms of geological hazards, 32 earthquakes of magnitude 5.0 or higher were reported in December, compared to 18 earthquakes recorded during December of 2017. However, none of the recorded seismic activities had significant effects to constitute a disastrous event. A M7.2 earthquake with a deep epicentre of 60 km below the earth’s surface was also reported near Davao Oriental, the Philippines, which triggered a tsunami warning – although the warning was eventually cancelled. In general, there were no fatalities or significant damage directly caused by earthquakes this month. However, there was one undetected tsunami event in Sunda Strait that caused significant number of fatalities and damage in Banten and Lampung Provinces of Indonesia. The tsunami, that struck on the evening of December 22, was triggered by landslide on Mount Anak Krakatau, that resulted from a series of eruptions and general increased volcanic activity on the mountain that sits in the middle of the Sunda Strait. From post-event observations, Mt. Anak Krakatau was found to have reduced in height from 1,800 metres to 357 metres, based on pre and post-tsunami images released by the Indonesian Agency for the Assessment and Application of Technology (BPPT). Consequently, the Centre for Volcanology and Geological Disaster Mitigation (PVMBG) elevated the alert status from advisory to watch (level III out of maximum IV).

OUTLOOK FOR JANUARY 2019

In the first week of the fortnight, a northeast monsoon surge is expected to cause wetter conditions in the South China Sea, particularly over coastal Thailand and Viet Nam. Related stronger monsoonal winds are likely to bring wetter weather to areas around the Java Sea as well. Conversely, drier conditions are expected over the Philippines. According to PAGASA climatology of tropical cyclones, there is a possibility of up to one tropical cyclone passing through the Philippines in January. Colder conditions in the highlands of the northern ASEAN region are forecasted. Following the cold conditions in the first week, should there be a sudden drop in temperatures, it might result in increased risk of flash floods with melting of snow or increased precipitation in the highlands.

Later in the month, the wetter conditions over the South China Sea are likely to spread further southward to affect the north-eastern coast of Peninsular Malaysia and southern Thailand. Thunderstorms are expected near the equatorial belt as the trade winds will bring heavier rainfall across the South China Sea towards Peninsular Malaysia and Singapore from the eastern front. Areas around the Java Sea are likely to become drier during this period.

The prevailing Northeast Monsoon is expected to persist until March 2019. This will bring occasional extended periods of dry weather in the northern ASEAN region during this period. Tropical storms and depressions will generally pass through Central and Southern Philippines, and towards Central and Southern Viet Nam bringing heavier rainfall in these regions. Cold spells will also be common in the northern lowland provinces of Viet Nam.

Written by : Qing Yuan Pang

GENERAL REVIEW OF JANUARY 2019

Statistics of recorded significant disasters in January 2019 are significantly below the average for the previous five-years during the same period. While January saw the ASEAN region only registered a little over half of the number of disasters, as well as significantly lower numbers of affected and internally displaced people, the number of casualties and damaged houses were notably much higher than the previous five-year average, with an almost two-fold number of casualties, and twenty times the number of damaged houses. These high numbers were primarily caused by flooding and rain-induced landslide incidents in South Sulawesi, Indonesia. This unfortunate event was a result of the combination of the prevailing Northeast Monsoon and Tropical Cyclone Riley in Australia, which pulled large masses of rain clouds over several parts of Indonesia.

The number of hydro-meteorological disasters is to be expected for this time of year, and influenced a majority of registered situations. Also as expected, due to the effects of the prevailing Northeast Monsoon, the affected areas were mainly found in the equatorial and southern parts of the ASEAN region. Meanwhile, the northern area is experiencing dry conditions, resulting in haze and hotspot situations. In terms of geophysical hazards, there were 65 recorded earthquakes with a magnitude 5.0 and above during January, and several activities reported on active volcanoes in Indonesia and the Philippines. Fortunately, although there were notable incidents such as the M6.7 earthquake in West Sumba Regency and the eruption of Mt Agung, both in Indonesia, there were no significant effects that constituted a disaster situation.

SEASONAL OUTLOOK

The ASEAN Specialised Meteorological Centre is expecting the Northeast Monsoon to persist until March, before entering into the inter-monsoon period in April. With this seasonal setting, the southern parts of the region will continue to experience scattered rain showers, while the northern areas will continue to experience dry conditions. Flood and rain-induced landslides will continue to be threats in the equatorial and southern parts, especially in areas where above-normal rainfall is expected – such as Malaysia, Sumatra, and Kalimantan. The continuous dry conditions and the expected above-normal temperatures in the north will likely exacerbate haze and hotspot situations, especially in the Mekong sub-region (see Figure 1).

Figure 2. The Rainfall and Temperature Outlook for the first half of February displays dry and warm conditions for some areas in the northern part of the region. Similar effects, with possible difference in spatial distribution, are expected to continue until March due to the Northeast Monsoon.

With these potential incidents, the AHA Centre is strengthening its Disaster Monitoring and Analysis Unit through an internship programme. Successful interns will help the Centre in monitoring hazards throughout the region on a daily basis, preparing necessary datasets, and analysing disaster events to support decision-making and drive actions.

Data Sources: ASEAN Disaster Information Network, ASEAN Specialised Meteorological Centre

Written by : Lawrence Anthony Dimailig

GENERAL OVERVIEW OF DECEMBER 2018

As generally expected for the “winter” or Northeast monsoon period, the southern part of ASEAN – particularly Indonesia, Malaysia, southern Philippines and Thailand – experienced an increase in floods during December 2018. Some areas within those countries also experienced landslides due to heavy rainfall in mountainous areas.

In terms of geological hazards, 32 earthquakes of magnitude 5.0 or higher were reported in December, compared to 18 earthquakes recorded during December of 2017. However, none of the recorded seismic activities had significant effects to constitute a disastrous event. A M7.2 earthquake with a deep epicentre of 60 km below the earth’s surface was also reported near Davao Oriental, the Philippines, which triggered a tsunami warning – although the warning was eventually cancelled. In general, there were no fatalities or significant damage directly caused by earthquakes this month. However, there was one undetected tsunami event in Sunda Strait that caused significant number of fatalities and damage in Banten and Lampung Provinces of Indonesia. The tsunami, that struck on the evening of December 22, was triggered by landslide on Mount Anak Krakatau, that resulted from a series of eruptions and general increased volcanic activity on the mountain that sits in the middle of the Sunda Strait. From post-event observations, Mt. Anak Krakatau was found to have reduced in height from 1,800 metres to 357 metres, based on pre and post-tsunami images released by the Indonesian Agency for the Assessment and Application of Technology (BPPT). Consequently, the Centre for Volcanology and Geological Disaster Mitigation (PVMBG) elevated the alert status from advisory to watch (level III out of maximum IV).

OUTLOOK FOR JANUARY 2019

In the first week of the fortnight, a northeast monsoon surge is expected to cause wetter conditions in the South China Sea, particularly over coastal Thailand and Viet Nam. Related stronger monsoonal winds are likely to bring wetter weather to areas around the Java Sea as well. Conversely, drier conditions are expected over the Philippines. According to PAGASA climatology of tropical cyclones, there is a possibility of up to one tropical cyclone passing through the Philippines in January. Colder conditions in the highlands of the northern ASEAN region are forecasted. Following the cold conditions in the first week, should there be a sudden drop in temperatures, it might result in increased risk of flash floods with melting of snow or increased precipitation in the highlands.

Later in the month, the wetter conditions over the South China Sea are likely to spread further southward to affect the north-eastern coast of Peninsular Malaysia and southern Thailand. Thunderstorms are expected near the equatorial belt as the trade winds will bring heavier rainfall across the South China Sea towards Peninsular Malaysia and Singapore from the eastern front. Areas around the Java Sea are likely to become drier during this period.

The prevailing Northeast Monsoon is expected to persist until March 2019. This will bring occasional extended periods of dry weather in the northern ASEAN region during this period. Tropical storms and depressions will generally pass through Central and Southern Philippines, and towards Central and Southern Viet Nam bringing heavier rainfall in these regions. Cold spells will also be common in the northern lowland provinces of Viet Nam.

Written by : Qing Yuan Pang

GENERAL OVERVIEW OF NOVEMBER 2018

November 2018 witnesses a two-fold increase in flood occurrences reported in comparison to the same period during 2017. As the region enters the “winter” monsoon period, the southern parts of ASEAN generally experience heavier rainfall, particularly in areas around the equator (shown in Figure 1) where precipitation patterns are generally higher. The heavier precipitation patterns (darker blue areas) are also brought about by typhoons and tropical storms, with these hydro-meteorological phenomena contributing to the increased flooding and collateral hazards (e.g. landslides) reported in the last month. An interesting note is that there was still drought reported in Indonesia – although this is coming to an end as the rainy season approaches.

In terms of geological hazards, 20 earthquakes of higher than magnitude 5.0 were reported during November 2018, compared to 22 during November 2017. Even though there were fewer reported earthquakes in 2018, the earthquakes were widely distributed across the boundary of the Indo-Australian plate, compared to being concentrated in the Ambon Sea in November 2017. Of concern are that 45% of these earthquakes were registered with a depth of less than 20km, which increases the likelihood of damage and disaster in nearby communities. In 2018, the reported earthquakes mostly occurred in areas with higher vulnerability – including in Eastern Indonesia and southern parts of the Philippines. There are currently six active volcanoes in Indonesia (Krakatau, Merapi, Agung, Semeru, Ibu and Dukono), as well as one in the Philippines (Mayon) on which recent volcanic activity has been reported.

OUTLOOK FOR THE DECEMBER 2018 – FEBRUARY 2019 PERIOD

There is an increased probability of above-average rainfall over the western equatorial region (parts of northern Sumatra, Peninsular Malaysia and Borneo). During this season, the monsoon rain band is forecasted to gradually shift south towards the Equator with an increased likelihood of shower activities and winds of light and variable direction. Shower activities are expected to persist until January 2019, reducing in the approach to February. Due to rainy conditions, hotspot activities in the southern ASEAN region are likely to remain activities in the southern ASEAN region are likely to remain subdued. Collateral hazards to heavy rains, such as landslides, should be monitored during this period, as heavier precipitation may trigger isolated incidents in hilly or mountainous areas.

Modeling has indicated that tropical Pacific Ocean sea surface temperature anomalies are not expected to warm much further. The probability of weak El Niño conditions occurring will peak during the October-December 2018 season, and will weaken beyond the first quarter of 2019. Due to the weak El Niño conditions, tropical typhoon forecasts remain at up to 3 potential typhoons until January 2019, with a slim chance of any forming during February*.

*) Information courtesy of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

Written by : Qing Yuan Pang