Viet Nam stands as one of the most disaster-prone countries in the ASEAN region, with over 70% of its dense population (almost 100 million people) often facing the adverse impacts of disaster – in particular due to hydrological events. Viet Nam’s geographical layout, population distribution, increased urbanisation and high numbers of vulnerable populations create a context for potential high-impact events within the nation’s borders, while climate change is also noted as having an increasing influence on the extremity of natural disasters in Viet Nam.
Viet Nam’s central and southern regions are particularly vulnerable to natural disaster events; however, its diverse landscape and topography ensure that all parts of the country are at high risk of natural disaster. The country is formed by mountainous areas, river deltas, highlands, islands and over 3,000km of coastline, with its tropical location causing monsoons, storms, floods and other events to strike the nation on a yearly basis. Viet Nam experiences both the northeast and southeast monsoon-winds, with its geographic layout meaning the nation is home two distinct climatic regions. All regions face extremely high rainfall levels, accentuated by a large system or rivers and deltas, resulting in ongoing vulnerability to flooding and other hydrological disasters.
Due to high rainfall, extreme weather occurrences, as well as the vast array of river and deltas across the nation, flood is one of the major types of disaster that affects Viet Nam’s population. The Northern river systems and basins account for over 75% of the north’s land area, resulting in multiple flooding events each year. Meanwhile in the Mekong river delta, floods are often generated from upstream events, resulting in inundation of the delta for months at a time. These events can have a severe impact on river-based communities – often threatening the lives, homes and livelihoods of the people who inhabit the river banks. Flash floods and mud floods also have great impact on mountain-based communities, caused by heavy rains and bad drainage systems. Such floods often strike communities across all four mountainous areas of Viet Nam, namely the north, central, central highlands and south-eastern regions.
Due to its location north-west of the Pacific Ocean, Viet Nam is one of the most storm-prone land masses in the world. Numbers of violent typhoons have continued to increase over recent decades, with the nation experiencing 10 to 15 typhoon events on average each year, historically affecting all geographic regions of Viet Nam. It is estimated that typhoons impact over 70% of Viet Nam’s population, with not only the initial storm, but the following heavy rains and floods also having an adverse effect on the nation’s communities.
LANDSLIDE AND EROSION
Landslide and erosion are also a common occurrence in Viet Nam, causing considerable losses to homes and agricultural land across the nation. Various natural and human activities cause such events, resulting in erosion to river banks, coastal areas, and multitudes of landslides on mountains and hillsides.
Viet Nam also experiences a range of other natural disasters across its landscapes, which although may pose limited short-term risk to human life, have an extensive impact on infrastructure, services and livelihoods within communities. Issues related to inundation are common, as are the impacts of drought and desertification. Cyclones are also an ongoing phenomenon, increasing in frequency with a changing climate.
Written by : William Shea
All information sourced from ‘Viet Nam Disaster Management Reference Handbook: 2015’, as developed by the Center for Excellence in Disaster Management and Humanitarian Assistance (CFE-DM).
MONTHLY DISASTER REVIEW AND OUTLOOK
MAY 2018 | DISASTER MONITORING & ANALYSIS
(DMA) UNIT, AHA CENTRE
GENERAL OVERVIEW OF MAY 2018
Hydro-meteorological hazards continued to form a majority of disasters within the ASEAN region during May 2018. Using yearly data comparisons, it is evidenced that the ASEAN region experienced twice as many disasters when compared to the same time period last year. Data for the initial three weeks of the period showed low numbers of recorded disasters. However, numbers increased significantly as Tropical Depression 5 developed and moved across Sulu Sea and into the South China Sea. This situation resulted in flooding, storm surges and strong wind events across Indonesia, the Philippines, Malaysia, Brunei Darussalam and Viet Nam. Monsoon season has begun in areas within proximity of the Indian Ocean, which creates increased flood risks for northern Myanmar along the Irrawaddy basin. This is consistent with ASEAN Specialised Meteorological Centre’s (ASMC) observation of the end of the dry season on the 16th of May, marked by an increase in shower activities across the northern part of the ASEAN region.
There were 37 moderate earthquakes with magnitudes of > M .4.0 felt in Indonesia and the Philippines, which were observed at around II to IV MMI. Despite the magnitude of such events, no casualties or damage was reported as a result of earthquakes in both countries. As of the end of May, the alert status for volcanoes in Indonesia are as follows – Warning Alert (Awas, the highest of 4 levels) for Mount Sinabung in North Sumatra; Watch Alert (Siaga, second highest) for Mount Agung in Bali; and Cautionary Alert (Waspada, a level 3 alert) for 19 other volcanoes across the nation. Despite its Cautionary alert level, Mount Merapi in Central Java, Indonesia, has experienced significant increased activity recorded on the mountain, with phreatic eruptions and release of volcanic ash columns beginning on the 21st of May. Three eruptions at the end of Week 22 (1st of June 2018) forced two airports in Central Java to temporarily shut down their operations as a result of the ash plume.
OUTLOOK FOR JUNE-JULY 2018
According to the ASMC, wet weather conditions are expected over the northern parts of the ASEAN region for the rest June, with more shower activities forecast as the transition to the Southwest Monsoon is expected to begin during the month. Rainfall can be expected to increase during this time due to the presence of the monsoonal rain band across the north of the ASEAN region. The Southwest Monsoon season typically prevails over the region between June and October, and is associated with the traditional dry season in southern parts of ASEAN contrasting with the wet season in northern parts of the ASEAN region.
In stark contrast to the northern ASEAN region, extended periods of dry weather can be expected during June and July in the southern reaches of ASEAN. This may lead to an escalation of hotspot activities, with smoke plumes should ignition occur, particularly in parts of Sumatra and Kalimantan. Slightly below-normal to near-normal rainfall may still occur over most parts of the region during this period, with below-normal to slightly below-normal rainfall expected for Java, Nusa Tenggara and Timor Leste during the early part of the Southwest Monsoon season.
As always, you should keep posted on weather updates from your respective Meteorological Services and Disaster Management Organisations for evacuation notices (if any). You can refer to our social media for links to the respective national agencies and organisations for further information.
Written by : Mizan Bisri, Qing Yuan Pang
AHA Centre’s estimation is based on data and information shared by National Disaster Management Organisations (NDMOs) and other relevant agencies from ASEAN Member States, international organisations and news agencies. Further information on each recorded-significant disaster, description and details of data and information are available at: http://adinet.ahacentre.org/reports.