Cyclone Ditwah ranks among the most severe flooding disasters to strike Sri Lanka in recent decades, according to new geospatial analysis released by the United Nations Development Programme (UNDP). The findings reveal that floodwaters submerged nearly 20% of the country’s land area, amounting to more than 1.1 million hectares.
The report further shows that 2.3 million people live within the inundated zones, with women representing more than half of the exposed population. Nearly 60% of those affected reside in the densely populated Colombo and Gampaha districts, where the pressure on essential services has intensified sharply.
UNDP warns that the crisis is deepened by existing economic vulnerabilities. More than half of the affected households were already grappling with instability, high debt, and poverty when the cyclone made landfall on 28 November.
UNDP Resident Representative Azusa Kubota cautioned that Sri Lanka cannot absorb additional debt to fund reconstruction in the wake of its recent economic crisis. She urged international partners to extend affordable financing, warning that the nation risks slipping off a “debt cliff” without urgent global support.
The physical destruction is vast. Nearly 720,000 buildings—roughly one in every twelve across Sri Lanka—are now situated in flood-affected areas. Damage to transport infrastructure is widespread, with 16,000 kilometres of roads and almost 500 bridges impacted. In the central highlands, around 1,200 landslides have isolated numerous remote communities.
Concerns over food security continue to grow, as floodwaters submerged 530,000 hectares of rice paddy, threatening future harvests and livelihoods.
Devanand Ramiah of the UNDP Crisis Bureau noted the rapid escalation of overlapping crises in Sri Lanka, stressing that recovery will be “slow and costly” in regions where severe flooding intersects with ongoing economic fragility.
In response, the UN and national authorities are urging scaled-up early recovery assistance to re-establish critical transport links and support the nation’s most vulnerable groups, including children and the elderly.