EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Attribution of 2009 extreme rainfall & landslide event in Austria 

Aditya Narayan Mishra1,2, Douglas Maraun1, Heimo Truhetz1, Raphael Knevels3, Emanuele Bevacqua4, Herwig Proske5, Helene Petschko3, Philip Leopold6, and Alexander Brenning3
Aditya Narayan Mishra et al.
  • 1Wegener Center, University of Graz, Graz, Austria
  • 2FWF DK Climate Change, Austria
  • 3Institute of Geography, University of Jena, Jena, Germany
  • 4Helmholtz Centre for Environmental Research, Germany
  • 5Institute for Information and Communication Technologies , FH Joanneum, Graz, Austria
  • 6Austrian Institute of Technology, Vienna, Austria

Between 22-26 June 2009, Austria witnessed a rampant rainfall spell that spread across populated areas of the country. High-intensity rainfall caused 3000+ landslides in southeast Styria, and property damages worth €10 Million in Styria itself. Elsewhere in Austria, flooding amounted to reparations worth €40 Million. Numerous synoptic-scale studies indicated the presence of a cut-off low over central Europe and excessive moisture convergence behind the extreme event. In a warmer climate change scenario, such an extreme precipitation event may manifest into a more intense event due to the higher water holding capacity of air with increased temperatures, but this reasoning may not be so straightforward considering the complex physics of precipitation, more so in a topographically heterogeneous region such as the GAR (Greater Alpine Region).

The flooding and landslides caused in the region raise an alarm and thus motivate this study whereby we investigate if the rainfall event did become stronger with time due to climate change compared to how it would have been in a counterfactual (climate change free) past. Here we have deployed the CCLM high-resolution regional model coupled with a statistical landslide model to simulate this event (rainfall and landslides) in a pseudo (surrogate) warming scenario. A marked decrease in rainfall intensity is observed in the simulations for 1° cooler climate (pre-industrial past) and the consequent landslide risk is reduced varying across GCMs that were used to derive the boundary conditions from.

We discuss the results from the lens of attribution perspective - how conditional attribution is much more useful compared to the conventional risk-based approach of attributing extreme events. The novelty of our approach lies in using a high-resolution convection-permitting regional model for a landslide attribution study.

How to cite: Mishra, A. N., Maraun, D., Truhetz, H., Knevels, R., Bevacqua, E., Proske, H., Petschko, H., Leopold, P., and Brenning, A.: Attribution of 2009 extreme rainfall & landslide event in Austria , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5845,, 2022.