Floods in the Mainland Southeast Asia (MSEA) can be caused by heavy monsoon rainfall, tropical cyclones and dam breaks. A recent study conducted by the research group led by Prof. Deliang Chen reveals that tropical cyclone induced floods have higher impacts, compared with the average impact of all types of floods. Prof. Chen is the leader for project “Climate Change and Water Resources in the Great River Regions in Southeast and South Asia” under the CAS Pan-TPE programme, and the August Röhss Chair at the University of Gothenburg.

The MSEA consists of five countries: Cambodia, Laos, Myanmar, Thailand and Vietnam, and landfalling tropical cyclones in the MSEA can induce severe flooding by the associated intense rainfall. Employing the Dartmouth Flood Observatory large flood data archive (http://floodobservatory.colorado.edu/Archives/index.html), this study estimates spatiotemporal change of occurrence and impacts of floods by all possible causes (ALLFloods) in the MSEA, and quantifies the contribution from tropical cyclone induced floods (TCFloods). Overall, ALLFloods have increased significantly during 1985 – 2018, while no significant change is found for TCFloods. However, ALLFloods’ (TCFloods’) impacts on human mortality have generally decreased significantly during 1985 – 2018 (1988 – 2018), although high-impact floods did occasionally occur. About 24.6% of all floods are caused by tropical cyclones; and TCFloods have higher impacts on human mortality and displacement rate than the average of ALLFloods.

Flood protection standards vary in the MSEA, which has implications for flood-induced mortalities. Higher flood impacts are found in Myanmar, which is at least partly caused by its relatively low flood protection standards. As previous studies from the research group projected rising future intensity of tropical cyclones influencing this area (Chen et al. 2020 Science Bulletin), results of this study point to increased flood risks associated with tropical cyclone in the MSEA.  

Ph.D. candidate Aifang Chen is the first author, and Prof. Deliang Chen is the corresponding author. This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA20060401), the China Scholarship Council, the National Natural Science Foundation of China (91537210), the Swedish STINT (CH2015–6226), and the Swedish VR (2017-03780).

Title of article: Flood impact on Mainland Southeast Asia between 1985 and 2018—The role of tropical cyclones

Link to article: https://doi.org/10.1111/jfr3.12598

Contact: Deliang Chen, professor at the Department of Earth Sciences, University of Gothenburg

Tel.: +46 (0)31-786 4813

The article was featured by PreventionWeb, the global knowledge sharing platform on disaster risk reduction, managed by the UN Office for Disaster Risk Reduction (UNDRR).