Cyclone Ditwah must be a turning point
When Cyclone Ditwah struck Sri Lanka in late November 2025, it caused a level of death and destruction the country had not experienced in decades. In just a few days, hundreds of lives were lost, many more went missing, and hundreds of thousands were displaced from their homes. Entire neighbourhoods along the major rivers were submerged. Roads and bridges were washed away. A reservoir dam at Mavil Aru reportedly failed, prompting emergency evacuations downstream.
For many Sri Lankans, this was more than a natural disaster. It felt like the system had failed them. As a Sri Lankan engineer and DRR specialist who has spent over a decade working on flood early warning systems (FEWS) internationally, I view Cyclone Ditwah not as a single catastrophe but as a stress test -and a wake-up call.
Sri Lanka does not need to start from zero. We have made significant progress. But this disaster starkly reveals that having an early-warning system is not the same as having an effective early-warning system.
Sri Lanka has long recognized the need for flood early warning systems. Over the years, government agencies, universities, and international partners such as the International Water Management Institute (IWMI) have developed hydrological models, created flood inundation maps, and conducted risk assessments for major rivers, including the Kelani and Kalu. Pilot flood-alert dissemination systems and upgraded telemetry networks have been introduced in select basins. Community-level preparedness drills have been carried out in a few locations.
These initiatives demonstrate solid scientific and technical understanding within the country. However, much of the work done by researchers on foreign-funded projects has not been translated into policies, engineering standards, planning decisions, or emergency-response protocols. Many promising pilot systems were not supported beyond the project cycle. Disaster preparedness still varies across regions, largely depending on local capacity and budgets. The result is a dangerous disconnect between knowledge and implementation, warnings without action, and information without protection.
Close research-to-action gap
Flood hazard maps and climate-risk projections, developed over years of research, have not been fully integrated into zoning laws or into critical infrastructure planning and maintenance. Similarly, advanced modelling tools exist but are not routinely operated, updated, or used to encourage proactive measures. Meanwhile, the most vulnerable communities often reside in unsafe locations – floodplains, steep hillsides, and informal settlements – where warnings alone cannot provide sufficient protection. Even with an SMS alert, if roads are submerged and shelters are unavailable, evacuation becomes impossible. Therefore, early warning systems must be combined with early action — and with safe alternatives.
What Ditwah revealed
Ditwah caused rainfall levels in some basins to exceed previous design assumptions, overwhelming drainage systems and pushing riverbanks and reservoirs beyond their capacity. Events once considered “rare” are now occurring with alarming frequency, showing that past hydrological data no longer reflect future risks.
The tragic impacts of Cyclone Ditwah cannot be solely attributed to hazard severity. They exposed systemic weaknesses, including:
- Warnings did not always lead to a timely response: Some people were unaware of the danger or did not understand the urgency. Others hesitated to leave possessions behind. Trust in official communication remains inconsistent.
- Dam safety and warning systems are not fully coordinated: The reported breach at Mavil Aru and pressure on other reservoirs highlight that coordination between hydropower and irrigation operations and downstream flood alerts is still insufficient. A failure upstream can result in a catastrophe downstream within minutes.
- Exposure has increased significantly: Rapid urbanization has placed homes, factories, and even hospitals in areas that were once safe flood retention zones. Unplanned development continues to expand risk faster than preparedness can provide protection.
- Infrastructure failed when it was most needed: Collapsed bridges, blocked roads, failing pumps, and disrupted communication networks hampered evacuation and slowed emergency response. Early warning cannot offset weak surrounding systems.
Governance — the missing ingredient
Technology alone is not enough. Data and forecasts cannot guide action unless supported by:
- Clear, coordinated institutional mandates
- Legally enforceable planning and safety standards
- Dedicated and sustainable funding for system maintenance
- Transparent communication and community trust
- Mechanisms for ongoing review and improvement
Early warning should be regarded as governance, not gadgets.
A key part of governance reform is strengthening collaboration between operational authorities and academic experts—ensuring scientific knowledge influences national practice, not just journal articles.
Road map for action
Based on lessons learned from Ditwah and global experience, Sri Lanka should prioritize the following:
1. Strengthen risk knowledge: Regularly update flood and landslide maps using new rainfall data, post-flood observations, and climate projections, and link risk maps to population and infrastructure exposure data.
2. Modernize monitoring and modelling: Upgrade river-gauge networks and connect them with real-time modelling and automated forecast triggers for early policy action, not late reactions.
3. Deliver impact-based warnings: Shift from technical signals (“water level rising”) to clear instructions (“three feet of flooding expected in your street — evacuate to this safe point”). Messages must be multilingual and reach everyone, especially those without smartphones.
4. Strengthen local readiness and anticipatory action: Ensure communities know where to go, when to go, and who will assist them. Evacuation pathways and shelters must be ready, accessible, and resourced.
5. Embed resilience in land-use and infrastructure: Stop approving new developments in high-risk floodplains. Retrofit key infrastructure — roads, electricity, pumping stations, communication networks — to remain operational during floods.
6. Reform institutions and build accountability: Establish a National Flood Risk and Early Warning Task Force involving government agencies, researchers, and civil society. Require post-event performance reviews and transparent progress reporting.
7. Create sustainable financing: Dedicate national funds for FEWS maintenance and upgrades, while leveraging climate finance and partnerships for long-term resilience.
Why it matters
Sri Lanka is becoming increasingly vulnerable to climate-related extreme events and is already experiencing stronger monsoons, changing rainfall patterns, and more intense cloudbursts than in the past. Without significant changes, disasters like Ditwah will occur more frequently and cause greater damage. However, a safer and more resilient future is entirely achievable.
Every rupee invested in preparedness yields many times its value through avoided damage, quicker recovery, and — most importantly — lives saved.
To move forward, we must focus on:
- Political commitment
- Responsible urban planning
- Proper investment in resilient systems
- Ending the cycle of short-term projects
- Valuing and applying our own scientific skills
Cyclone Ditwah demonstrates that Sri Lanka already has many of the technical building blocks—gauge networks, centralized DMC operations, local and global partnerships —but these must now be woven into a next-generation, impact-based FEWS that matches the reality of a changing climate and rapidly urbanizing floodplains.
The choice before us is clear. We can see Ditwah as a regrettable, once-in-a-generation anomaly, or as a turning point in how Sri Lanka understands and manages flood risk. I believe it should be the latter. With targeted investment, strong institutional coordination, and ongoing community engagement, flood early warning systems can evolve from merely a technical function in Colombo to a trusted, life-saving practice across the island.
We owe it to the families who lost loved ones, to the children whose homes were washed away, and to every community living in fear of the next heavy rainfall.
Disasters may be unavoidable – but the extent of human suffering is not.
(The writer is a civil engineer & hydrologist specializing in Flood Risk Management and Early Warning Systems, and a former Senior Researcher at the United Nations University)
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