Prof. Timothy Dube from UWC’s Institute for Water Studies contributed to global research analysing extreme flood impacts worldwide in 2025
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Floods caused more than 4200 deaths and over US$28 billion (R461 billion) in damages worldwide in 2025.
This is according to an international study involving researchers from UWC, and published in the journal Nature, which identified 2025 as one of the most hydrologically extreme years across Africa in recent decades.
This has resulted in elevated river flows, widespread displacement and severe flooding recorded in several regions.
Drawing on high-resolution global hydrodynamic modelling, the research analysed extreme flood events and population exposure across every continent. The international team included Professor Timothy Dube from UWC’s Institute for Water Studies.
The findings showed flood disasters were shaped not only by rainfall intensity, but by the interaction between extreme weather, saturated soils, river systems and settlement patterns.
Using a high-resolution global hydrodynamic modelling platform, the team mapped extreme river flows and population exposure throughout 2025. The analysis found that flood anomalies were geographically concentrated, shaped by large-scale atmospheric circulation and ocean-atmosphere variability.
The researchers noted that existing hydrological conditions worsened the impact of heavy rainfall in several regions.
In the USA, flash floods in Texas resulted from intense convective storms falling on drought-affected catchments, producing abrupt peak flows and significant loss of life. In southern Brazil, renewed rainfall over already saturated basins triggered widespread re-flooding, prolonging disruption after the devastating 2024 events.
Across Africa, some of the most severe impacts were recorded around Lake Tanganyika, where prolonged seasonal rainfall caused sustained flooding and displacement.
The Eastern Cape was also highlighted after a slow-moving cut-off low system dumped more than 300mm of rain within 48 hours, leading to infrastructure damage and fatalities.
The analysis also showed that Asia accounted for approximately 56% of the global population exposed to extreme river flows, with intensified monsoon rainfall, typhoons and cyclonic systems driving large‑scale flooding and fatalities across South and Southeast Asia.
The study stressed that its flood maps represent hydrological extremity and flood potential rather than uniform flooding.
“Hotspots of elevated annual maximum streamflow identify locations experiencing anomalously high peak flows, but do not imply that flooding occurred uniformly across these areas” the authors explained.
By combining global modelling with reported disaster impacts, the research underscores the growing importance of early warning systems, preparedness and anticipatory capacity.