Cyclone Ditwah triggered one of the most severe flood disasters inSri Lanka’s recent history, with the United Nations Development Programme (UNDP) reporting that 1.1 million hectares, nearly 20% of the country’s land, were submerged.
Thecyclonemade landfall on November 28 along the eastern coast, unleashing relentless rainfall that caused widespread flooding and over 1,200 landslides across multiple districts. According to a joint assessment by UNDP and Sri Lanka’s Disaster Management Centre, around 2.3 million people were directly exposed to cyclone-driven flooding.
The report highlights that the disaster’s physical impacts have been intensified by deep pre-existing socioeconomic vulnerabilities. Nearly 720,000 buildings were exposed to floodwaters, including 243 hospitals and hundreds of schools. Severely affected regions such as Dimbulagala in Polonnaruwa, Kandavalai in Kilinochchi, and Maritimepattu in Mullaitivu witnessed extensive inundation, while highland districts like Nuwara Eliya, Badulla and Kegalle faced heavy rain-induced landslides.
UNDP’s analysis, which integrates satellite-based flood mapping, landslide data, infrastructure exposure and population density with its Multidimensional Vulnerability Index, warns that over half the people in flooded zones were already living with multiple vulnerabilities, including unstable income and high debt. The cyclone also damaged essential infrastructure, with more than 16,000 km of roads, 278 km of railway lines and hundreds of bridges affected.