Articles | Volume 25, issue 2
https://doi.org/10.5194/nhess-25-581-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/nhess-25-581-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Causes of the exceptionally high number of fatalities in the Ahr valley, Germany, during the 2021 flood
Belinda Rhein
CORRESPONDING AUTHOR
Section Hydrology, GFZ Helmholtz Centre for Geosciences, Potsdam, Germany
Geography Department, Humboldt-Universität zu Berlin, Berlin, Germany
Section Hydrology, GFZ Helmholtz Centre for Geosciences, Potsdam, Germany
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Cited
19 citations as recorded by crossref.
- Assessing the impact of early warning and evacuation on human losses during the 2021 Ahr Valley flood in Germany using agent-based modelling A. Silva et al.
- Climate change and brain health, a risk management approach focusing on the European region: A narrative review J. Reis et al.
- Rainfall patterns and their association with flood fatalities across diverse Euro-Mediterranean regions over 41 years K. Papagiannaki et al.
- Mortality reduction despite changing climate extremes requires better understanding of human behavioral response to warnings P. Bubeck et al.
- A capital city at risk and no transformation of urban development? Forensic disaster risk assessment in the case of Ulaanbaatar in Mongolia A. Fekete
- A framework for generating catalogues of high-impact UNSEEN flood events E. Bianco et al.
- Understanding vulnerability to flood-induced disasters: a comprehensive scoping review on at-risk individuals and evacuation challenges C. Del Prete et al.
- Loss of Life in River and Flash Floods in Europe: Evaluation of Deterministic Approaches and Implications for Risk Assessment D. Bekić
- Comparing flood forecasting and early warning systems in northwestern Europe T. Busker et al.
- The Potential of EO Data for Enhanced Flood Monitoring and Forecasting: A Consortium Assessment A. Tarpanelli et al.
- Deciphering the drivers of direct and indirect damages to companies from an unprecedented flood event: A data-driven, multivariate probabilistic approach R. Guntu et al.
- Quantitative scenario- and expert-based vulnerability assessment: transdisciplinary methodology and application in Germany’s health care system R. Scholz & T. May
- Signals without action: a value chain analysis of Luxembourg's 2021 flood disaster J. Da Costa et al.
- The deadliest sudden weather-related events in the Czech Lands, 1851–2025 CE R. Brázdil et al.
- Prototype citizen and community science app for urban heavy rainfall risk management in the Ahr Valley, Germany J. Hoffmann et al.
- Impact-Based Decision Making in Flood Risk Management: A Review of Behavioral and Technical Approaches Z. Bovermann et al.
- Closing the gap: Bridging research and practice to implement best practices in disaster warning communication F. Meissner et al.
- Comparative Analysis of Evacuation Processes in Response to Fluvial Floods: Selected Regions in Germany and Poland M. Borowska-Stefańska et al.
- Expert insights into the health and societal risks of a potential AMOC collapse in Europe: Focus on Germany J. Mirow & S. Wheat
19 citations as recorded by crossref.
- Assessing the impact of early warning and evacuation on human losses during the 2021 Ahr Valley flood in Germany using agent-based modelling A. Silva et al.
- Climate change and brain health, a risk management approach focusing on the European region: A narrative review J. Reis et al.
- Rainfall patterns and their association with flood fatalities across diverse Euro-Mediterranean regions over 41 years K. Papagiannaki et al.
- Mortality reduction despite changing climate extremes requires better understanding of human behavioral response to warnings P. Bubeck et al.
- A capital city at risk and no transformation of urban development? Forensic disaster risk assessment in the case of Ulaanbaatar in Mongolia A. Fekete
- A framework for generating catalogues of high-impact UNSEEN flood events E. Bianco et al.
- Understanding vulnerability to flood-induced disasters: a comprehensive scoping review on at-risk individuals and evacuation challenges C. Del Prete et al.
- Loss of Life in River and Flash Floods in Europe: Evaluation of Deterministic Approaches and Implications for Risk Assessment D. Bekić
- Comparing flood forecasting and early warning systems in northwestern Europe T. Busker et al.
- The Potential of EO Data for Enhanced Flood Monitoring and Forecasting: A Consortium Assessment A. Tarpanelli et al.
- Deciphering the drivers of direct and indirect damages to companies from an unprecedented flood event: A data-driven, multivariate probabilistic approach R. Guntu et al.
- Quantitative scenario- and expert-based vulnerability assessment: transdisciplinary methodology and application in Germany’s health care system R. Scholz & T. May
- Signals without action: a value chain analysis of Luxembourg's 2021 flood disaster J. Da Costa et al.
- The deadliest sudden weather-related events in the Czech Lands, 1851–2025 CE R. Brázdil et al.
- Prototype citizen and community science app for urban heavy rainfall risk management in the Ahr Valley, Germany J. Hoffmann et al.
- Impact-Based Decision Making in Flood Risk Management: A Review of Behavioral and Technical Approaches Z. Bovermann et al.
- Closing the gap: Bridging research and practice to implement best practices in disaster warning communication F. Meissner et al.
- Comparative Analysis of Evacuation Processes in Response to Fluvial Floods: Selected Regions in Germany and Poland M. Borowska-Stefańska et al.
- Expert insights into the health and societal risks of a potential AMOC collapse in Europe: Focus on Germany J. Mirow & S. Wheat
Saved (final revised paper)
Latest update: 05 May 2026
Editorial statement
The paper explains the factors which made the Ahr flood event of 2021 the deadliest one in Germany, causing more fatalities than all flood events of the previous 40 years together. It points out that 75% of the fatalities occurred outside of the established flood hazard zones. On the basis of individual fatality reports, factors additionally to early warning and evacuation deficits are identified. A particular result is that beyond danger zones like campsites and cellars the percentage of deaths on the ground floor of buildings (37 %) or outside on the street (18 %) were particularly high. Recommendations for improving emergency management of such unprecedented floods are given.
The paper explains the factors which made the Ahr flood event of 2021 the deadliest one in...
Short summary
In July 2021, flooding killed 190 people in Germany, 134 of them in the Ahr valley, making it the deadliest flood in recent German history. The flash flood was extreme in terms of water levels, flow velocities and flood extent, and early warning and evacuation were inadequate. Many died on the ground floor or in the street, with older and impaired individuals especially vulnerable. Clear warnings should urge people to seek safety rather than save belongings, and timely evacuations are essential.
In July 2021, flooding killed 190 people in Germany, 134 of them in the Ahr valley, making it...
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