Natural disasters not only result in death and destruction but can also undermine decades of development gains. The vast majority of the natural disasters affecting Sri Lanka are hydro-meteorological in origin. Sri Lanka is not known to be prone to earthquakes and volcanoes but is prone to tsunamis.
Advances in technology and a hazard warning system can be used to predict risk levels of floods, cyclones and landslides a few days in advance and the tendency to drought months in advance. The risk levels of these hazards can be predicted with a degree of confidence so as to be useful for natural resource managers, policy and decision makers.

The flood hazard maps show high risk in western, south-western, northern, north-eastern and eastern parts of the country. The region with steep slopes facing the west and east are at risk. Floods occur in the Central Hill slopes and in the eastern coastal area during the Maha rainfall season from September to January. In the western slopes, floods occur in the Maha rainfall season but are more common in the mid-Yala season from May to August. These trends are reflected in both hazard risk seasonal maps .

Heavy rainfall climatology in the eastern and south-western slopes are a principal cause of the flood risk. In addition, the drainage and topography of certain districts and land use patterns are also significant factors.

The frequency during the period 1947-1996 for each Divisional Secretariat Division was used as the risk factor for landslides.

The landslide hazard is localized in eight districts in the central highlands. The western slopes (Kegalla, Ratnapura and Nuwara Eliya) show higher risk with marked spatial variability within each district. The frequency and magnitude of landslides have increased in recent years.

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Storms and cyclones from the Bay of Bengal pass through the island preponderantly during the last four months of the Gregorian calendar year. There have been four severe cyclones during the last 100 years as well as a number of severe and moderate storms.

Using the available cyclone tracks for the last 100 years, a cyclone hazard risk map was constructed by counting the how often a cyclone or storm passed through each district. Additional weight was given to the cyclones over the storms. The index was normalized by the area and mapped as shown.

Higher risk is evident in the Eastern seaboard and the Northern part of the island. Cyclone incidence shows a strong seasonality. The main cyclone season is from November to December accounting for 80% of all occurrences.

Two distinct regions emerge as areas that have higher risk for hazards. One is the South-Western hill slopes region, and the other is the North-Eastern coastal region. Kegalle, Ratnapura, Batticaloa, Ampara, Galle and Mullaitivu Districts are prone to the highest risk.

In the North-East region, the Eastern coastal belt along with Anuradhapura, Mannar and Vavuniya Districts show higher risk, albeit less than the Western slopes. In addition, the Southern districts of Hambantota and the North-Central district of Puttalam also are under risk from multiple hazards.

Disasters occur when vulnerable communities, their infrastructure, economic activities and livelihoods are exposed to a hazard. Vulnerability can be estimated for people, economic activities and infrastructure as a measure of disaster proneness. Spatial estimates for Sri Lanka are shown below. Population density (top left) shows the relative human exposure to hazards. The food insecurity index calculated by the World Food Programme (map top right) shows the relative level of vulnerability. Industrial output and agricultural production maps ( bottom right and left) indicate areas more vulnerable to disruption of economic activities.

• June 2006: in press, Lareef Zubair, Vidhura Ralapanawe, Upamala Tennakoon, Zeenas Yahiya and Ruvini Perera, Natural Disaster Risks in Sri Lanka: Mapping Hazards and Risk Hotspots , World Bank Working Paper, Washington, D.C.

• November 2004: May 2003 disaster in Sri Lanka and Cyclone 01-B in the Bay of Bengal, Natural Hazards, 33: 303-318, 2004.

• July 2003: with U. Tennakone, Z. Yahiya, J. Chandimala & M.R.A. Siraj, What led to the May 2003: Floods?, Journal of the Institute of Engineers, Sri Lanka, XXXVI (3): 51 – 56.

• March 2003: Lareef Zubair, Vidhura Ralapanawe, Upamala Tennakoon and Ruvini Perera, Contributions to the Disasters Section of the National Atlas of Sri Lanka, forthcoming, 2nd Edition.

• March 2003: Lareef Zubair, submitted, Cyclone Hazards and Response in Sri Lanka, Journal of the Institute of Engineers.

• August 2003: What led to the May Flooding, The Island, National Newspaper, Sri Lanka, August 23, 2003.

• Mar 2005: Lareef Zubair, Using Climate Information for Disaster Risk Identification in Sri Lanka, Climate Prediction Applications Science Workshop March 15-17, 2005, Palisades, New York.

• December 2004: Lareef Zubair, Using Climate Information for Disaster Risk Identification in Sri Lanka, Annual Meeting of the American Geophysical Union, San Francisco.

• October 2003: Vidhura Ralapanawe and Lareef Zubair, Assessment of High-Risk Natural Disaster Hotspots of Sri Lanka, 2003 Open Meeting of the Human Dimensions of Global Environmental Change Research Community, Montreal, Canada

• Feb 2005: Lareef Zubair, Vidhura Ralapanawe, Upamala Tennakoon, Ruvini Perera, Fine Scale Natural Hazard Risk and Vulnerability Identification Identified by Climate, Submitted to IRI.