FAO Home







Sri Lanka



Land assessment

Type of Damage

Damage classification


Salinity Recovery

Impacts of subsidence on coastal areas



Damage and recovery capacity

Tsunami in perspective

Human tragedy, more than physical damage,
places the Tsunami among worst water-related disasters ever.

Pieter Waalewijn and Daniel Renault ¹

From a low ranking for flooded/affected areas...
..to an extremely high death toll
Vulnerability, hazards and resilience
back to top

The tsunami that ravaged the coasts of the Indian Ocean on the morning of 26 December 2004 will be in global collective memory for many years. The tsunami hit the coast of 12 countries and the victims represent more than 40 nationalities, making this a disaster of global proportions. The sudden disaster directly affected many people, and subsequently aroused concerns and compassion from all over the world. Many factors influence the impact of a disaster. This paper will take the impact of the flood on the agricultural sector as a starting point. Amidst all confusion and pledges for help there was a sensation that this might be the biggest flood or natural disaster in recorded history. Dazzling figures soon showed that it was not the largest, but still one of the deadliest of recent history. Now that damage assessments have been completed and rehabilitation is ongoing, it can be worthwhile to compare the extent of the tsunami-flood with other floods. Flood data are always complex and fuzzy, as it is hard to tell in an emergency what the exact extent of the particular event was. Nevertheless, this comparison can put the disaster in the right perspective and point at the critical elements in this particular disaster to be accounted for in (agriculture) rehabilitation strategies.

back to top From a low ranking for flooded/affected areas.......
On 22 December 2004 heaviest rains in 20 years resulted in overflowing of the rivers in the Cape Provinces of South Africa. Roads and Bridges were swept away. For the people who were affected it is an event that will not soon be forgotten. It can be assumed, however, that the majority of the world population has never heard about this flood. Still, the affected area is almost as big as the entire area affected by the tsunami. The largest flood of 2004 in terms of area affected was caused by heavy rain in Brazil. More than 2 million square kilometres were affected². The table below gives figures for the largest floods of 2004 (in sq. km.).



Affected Area (km²)

Main Cause





Heavy rain





Monsoonal rain



India , Bangladesh , Myanmar


Monsoonal rain



Russia and Belarus


Rain and snowmelt



India and Pakistan


Monsoonal rain


Table 1: Five largest floods in 2004 (in terms of total area affected) Based on: Dartmouth Flood Observatory, 2004 (DFO).

On this list, the tsunami would occupy the 53 rd place with 55,440 km², immediately after the flood of the Crooked Creek in the USA , killing 3 people and little above the December 22 flood in South Africa . Since December 26 (until 5/5/2005 ) there have been 23 floods with a larger affected area than the tsunami, the largest of which is the recent flooding of the Danube in March/April with an affected area of 673,500 km² (DFO, 2005). These figures are very high and do not refer only to arable land, the main concern of this article. As far as known from all 2004 disasters, the largest affected areas of arable land were:



Agriculture areas flooded (hectares)

Main Cause



China ( Upper Yangtze )


Heavy Rain





Heavy Rain



(Northern) Thailand


Heavy Monsoon



China (Huai He Tributaries)


Heavy Rain



Bosnia , Croatia and Romania


Heavy Rain


Table 2: Five largest floods in 2004 (in terms of agricultural area affected) Based on: Dartmouth Flood Observatory, 2004.

With around 65,000 agriculture hectares affected (FAO, 2005), the tsunami occupies a modest 9 th place in this list. These figures give the impression that the tsunami is not a very large disaster, and it wasn't in this respect. Although water-related disasters are on the increase, 2004 was not an exceptional year. Every year dozens of floods inundate areas that are ten times larger than that of the tsunami.

Map 1: Major floods reported in 2004. Source: Dartmouth Flood Obseratory, 2004.

In another respect, however, the tsunami stands out among 2004 floods. With regard to economic damage, the tsunami competes with the Rananim Typhoon in China . Both disasters caused damages of over 2 billion USD (DFO, 2004). The EMDAT Emergency Disaster Database of OFDA/CRED gives higher estimates for total tsunami damages (almost 8 billion USD), but that is only slightly more than estimated damages of monsoon floods in Bangladesh and three consecutive typhoons that passed over the United States of America in 2004. For comparison, the natural disaster causing most economic damage in 2004 was the October Niigata earthquake ( Japan ) with an estimated damage of 28 billion USD (EMDAT, 2005); an event hardly noticed by the global community.

Satellite images of Banda Aceh before and after the waves. Across the whole region, people lived close to the shore, that was never considered a threat before.

back to top.......to an extremely high death toll

Technically speaking, the effects of the tsunami were minor (or average) if compared to other floods. Most striking, however, is the death toll of the tsunami. An estimated 250,000 people have been killed by the waves. Notwithstanding the small area affected, this is by far the highest death toll of a flood in recent years. Other floods of 2004 with high numbers of casualties were May and September (Hurricane Jeanne) floods in Central America and monsoon-induced floods in India, Bangladesh and Myanmar, all taking 'only'3,000 lives. With 5 million people displaced after the tsunami, the tsunami also has a much wider effect than most of the other floods. Only the above-mentioned monsoon-floods caused more people to (temporarily) leave their homes.

It is clear that the impact of the disaster has everything to do with the human dimension. EMDAT gives a list of the worst floods of the last century. This shows that the December 2004 Tsunami is one of the worst flood disasters ever in terms of human death toll.


Countries most affected by Water-related Disasters (1900-2005)
sorted by number of people killed and affected







People Affected

China P Rep




China P Rep



China P Rep




China P Rep



China P Rep




China P Rep



Indian Ocean




China P Rep



China P Rep




China P Rep



China P Rep







China P Rep




China P Rep







China P Rep



China P Rep




China P Rep







China P Rep







~ Indian Ocean

Dec- 2004


Table 3: Countries most affected by Water-related Disasters (1900-2005). Based on: "EM-DAT: The OFDA/CRED International Disaster Database, Université catholique de Louvain , Brussels , Belgium ".

back to topVulnerability, hazards and resilience
The above shows the obvious: not all floods are disasters and disasters are complex events with many dimensions. The tsunami is a grave disaster, mainly because of the number of casualties. That is what distinguishes it from the South African flood for example.
In disaster studies use is often made of the simple equation:

Risk = Hazard * Vulnerability

In the equation 'risk' stands for the probability of harmful consequences that result from the interaction of hazards and vulnerable conditions. Hazards are natural or human-induced potentially damaging events. Vulnerability refers to the degree to which a society is susceptible to the impact of hazards. Vulnerability has technical, social, economic and political dimensions, as these all influence the exposure of one's livelihood to a disaster. In this way of thinking 'natural disasters' can have a large human component: obviously in the vulnerability, but also in the hazard. The increase of water-related disasters in recent history has to do with both sides of the equation. More and more people inhabit low-lying delta areas that are prone to inundation, and intensity and frequency of hazards increase due to human-induced factors, i.e. deforestation, canalisation and climate change.

The mosque of Meulaboh still stood after the Tsunami, surrounded by debris of wooden houses, boats, etc. More than half of the population of the city was reported dead or missing (more than 20,000 people).

The reason that most floods do not cause these high numbers of casualties is that people in disaster-prone areas have learned to cope with the floods, either by reducing the hazard or the vulnerability. The victims of the tsunami, however, were hit by a disaster resulting from a hazard that was unknown. They were unprotected from the hazard, unaware of the risk and unprepared for the disaster that suddenly struck them. In a way, the tsunami was a rare case of 'real' natural disaster, as it was not in any known way induced by humans, nor were victims aware of warning signals such as the receding of the sea.

Still, the impact of the disaster was different for more vulnerable groups. Concrete dwellings offered better protection than wooden houses. Unwittingly, people staying in concrete homes or further from the coast were less vulnerable to the hazard. (This is not an economic division however, as the numerous wooden beach-front tourist bungalows were as vulnerable as the simple huts of fishermen.)

Mitigating disaster risks needs to focus on reduction of hazards and vulnerabilities. With an unpredictable tsunami-hazard, reduction of the hazard is unlikely. The special cause of the floods - not by high rainfall or snowmelt and swelling of rivers - resulted in a very widespread and scattered flooded area. The total area is small, but it covers a stretch of thousands of kilometres of coast in 12 countries. Not much can be done to block the waves, but integrated coastal area management (ICAM) can serve to diminish the impact of the waves. It should be accepted that the waves can come a second time, with the same force, covering the same area. As the figures tell, the flooded area is very small, but costs of protecting would be enormous and will have numerous undesired side-effects. The scattered and long coastal stretch can not be protected.

A woman weeps over the loss of her three children at Tharangambadi, India, Thursday, Jan. 6, 2005. [AP]

The biggest improvement in risk management can be achieved by targeting on the vulnerabilities of the coastal communities. ICAM can reduce vulnerability in a technical way. Reconstruction of facilities can take into account the different coastal zones, so that critical services for agriculture (markets/suppliers/ storehouse/veterinary services) as well as farm dwellings are located further from the shore, thereby greatly improving the resilience of the agro-ecological system. The fact that the flooded area is a long and narrow stretch has thus both advantages and disadvantages for recovery. An early warning system will be another useful technical means to reduce vulnerability.

Social and economic vulnerability reduction strategies would include capacity building of communities. Awareness raising (or in this case, maintaining awareness) on what to do in the occurrence of a similar disaster and increasing local purchase power are ways to strengthen local coping mechanisms. National and local government and other supporting organisations should regularly update disaster preparedness plans, so that recovery can be swift. This needs strong political commitment and the understanding that the heaviest impact of the tsunami was on people, their livelihoods and their capabilities, and not so much the technical damage. The (ICAM) strategies need to focus also on the structural causes of vulnerability. Land zoning is not simply changing the habits of the coastal communities. It is likely that there are many social, economic and political reasons why people live in crowded villages near the shore. ICAM strategies must incorporate the aspirations of the communities and address factors that inhibit them from diversification and change of landuse, making it a complex and political process. Already in this stage of the recovery process, peoples' capabilities should be tapped and enforced. Since the communities lost many of their members, capacities should be redeveloped, also in the agricultural sector.

Salinity Training in Sri Lanka. Capacitating communities to assess and manage damages of the tsunami themselves builds confidence and is a first step towards sustainable rehabilitation.

back to topConclusion
To conclude, it can be stated that although the tsunami affected area was small and damages average, the disaster heavily affected the coastal communities as they were unprepared for the disaster. (Agriculture) rehabilitation should, more than at present, account for this human dimension of the tsunami. Mere reconstruction does not suffice, as it does not target the most critical causes of the tragedy. Land zoning will be very useful, but only if it focuses on vulnerability in more than only the technical sense. Finally, vulnerability of coastal community to the tsunami-threat should be viewed in a broader sense. Where the tsunami-hazard is unpredictable and perhaps small, risks exist in other areas as well, as was demonstrated by the heavy floods that added to the disaster in part of the tsunami-affected region. A stronger focus on the complex interplay between society and the agro-ecological system is needed to ensure the regrowth of thriving agricultural communities along the Indian Coast .
¹ Pieter Waalewijn is consultant with FAO-Agriculture Department on the Tsunami. Daniel Renault is senior officer in the FAO Land and Water division and tsunami-focal point for the Agriculture Department of FAO.
² These are not flooded areas but rather the extent of geographic regions affected by flooding. Source: Dartmouth Flood Observatory
³ Still, the impact of the disaster was different for more vulnerable groups. Concrete dwellings offered better protection than wooden houses. Unwittingly, people staying in concrete homes or further from the coast were less vulnerable to the hazard. (This is not an economic division however, as the numerous wooden beach-front tourist bungalows were as vulnerable as the simple huts of fishermen.)

back to top References
•  Brakenridge, G.R., Anderson, E., Caquard, S., 2004, Global Register of Major Flood Events, Dartmouth Flood Observatory, Hanover, USA, digital media, http://www.dartmouth.edu/%7Efloods/Archives/2004sum.htm
•  Brakenridge, G.R., Anderson, E., Caquard, S., 2005, Global Register of Major Flood Events, Dartmouth Flood Observatory, Hanover, USA, digital media, http://www.dartmouth.edu/%7Efloods/Archives/2005sum.htm
•  EMDAT-data drawn on 5/5/2005 from: "EM-DAT: The OFDA/CRED International Disaster Database - www.em-dat.net - Université Catholique de Louvain - Brussels - Belgium ", http://www.em-dat.net/index.htm
•  FAO, 2005, A regional strategic framework for reclamation of salt-affected soils and agriculture recovery in tsunami-affected areas, http://www.fao.org/ag/tsunami/home/home.html



FAO Regional Framework for Agriculture Recovery

Related links

2004 Flood Archive

OFDA / CRED Disaster Database

Water Resources, Development and Management website

 contact: tsunami@fao.org

© FAO, 2005