Areas flooded 1.1 hectares

Population exposed 2.3 mn

Landslides recorded 1.2 k = Buildings exposed 919 k

The UNDP has estimated that almost 720 thousand buildings were exposed to cyclone-related flooding across Sri Lanka. According to UNDP analysis, this includes 243 hospitals (as estimated by the Sri Lankan Ministry of Health) and hundreds of educational facilities. Overall, about 1 in every 12 buildings in Sri Lanka was exposed to flooding during Cyclone Ditwah, the UNDP stated.

At the level of divisional secretariats, Ja-Ela in the Gampaha district recorded the highest number of affected buildings with more than 44 thousand structures exposed. Kolonnawa and Kaduwela in the Colombo District as well as Katana and Wattala in the Gampaha District also recorded over 35 thousand exposed buildings each, according to the UNDP.

The flooding was so severe Cyclone Ditwah resulted in 1.1 million hectares of flooding across Sri Lanka – equal to about 20% of Sri Lanka’s land mass, the UN agency stated.

Based on the Department of Surveys’ 2024 national road dataset, the UNDP analysis estimated that more than 16 thousand kilometers of roads were exposed to flooding across the country, enough to circle Sri Lanka’s coastline 12 times over. The cyclone has also exposed over 480 road bridges nationwide.

At the level of divisional secretariats, Katana, Gampaha, and Ja Ela in the Gampaha District all recorded over 300 km of exposed roads each. Other secretariats like Kaduwela in the Colombo District and Wattala in the Gampaha District also registered high levels of road exposure.

Railways and railway bridges (railroad system), too, suffered significant damages according to the UNDP analysis. Accordingly, over 278 km of railways were exposed to cyclone-related flooding, including 35 railroad bridges nationwide. The UNDP emphasized that this figure reflected flooding only, but other hazards (such as localized debris, landslides, or damage to a single bridge) could also disrupt operations, meaning that even relatively small obstructions could render long stretches of railway non-operational. Like road exposure, railway exposure limits mobility and the capacity of affected populations to access key services and infrastructure.

At the level of divisional secretariats, Colombo and Thimbirigasyaya in the Colombo District, Ja Ela in the Gampaha District, as well as Mannar Town and Nanaddan in the Mannar District all registered over 10 km of exposed railways each.

The UNDP has warned the removal of debris posed quite a challenge with preliminary estimates indicating that Cyclone Ditwah generated more than 240,000 tonnes of non-construction waste and over 60,000 m³ of construction-related debris. These figures were expected to increase and evolve as field verification advances and more areas become accessible, the UNDP stated.

The UNDP dealt with the crisis experienced by the agriculture sector.

The UNDP stated: “It is estimated that Cyclone Ditwah has exposed over 530 thousand hectares of paddy lands to flooding across Sri Lanka. The most impacted divisional secretariat is Dimbulagala (Polonnaruwa District) with almost 19 thousand hectares of exposed paddy lands. Other secretariats like Welikanda and Medirigiriya, also in the Polonnaruwa District, as well as Horowpathana (Anuradhapura District) and Dehiattakandiya (Ampara District) have also been heavily affected by cyclone-related flooding. There are also areas where 20 to 30% of households do not have sufficient stocks of dry food (such as rice) to last at least a week. Therefore, it is clear that the cyclone’s agricultural impacts are also located in areas with a high degree of food-related vulnerability.”

A key finding of latest UNDP analysis is that over half of the people in flooding areas were already living in households facing multiple vulnerabilities before Cyclone Ditwah, including unstable income, high debt, and a limited capacity to cope with disasters. These communities face heightened challenges in recovery, underscoring the need for targeted interventions.

According to the UNDP major recovery needs were concentrated in areas where cyclone impacts intersect with preexisting multidimensional vulnerability. “This pattern is evident across the central highlands and the northern, western, eastern, and central regions. Among the divisional secretariats with the highest recovery needs are Mundel and Arachchikattuwa in the Puttalam District, as well as Kandavalai in the Kilinochchi District.”