Attribution of Extreme Rainfall Associated with the Balkans Floods of May 2014

In May 2014, the Balkan Region experienced exceptionally heavy rainfall. Between May 14 and May 19, 2014, there was a devastating flood in Serbia, Croatia, and Bosnia & Herzegovina. The event shattered a number of historical records and seriously endangered economies across the region. The close proximity of human settlements, infrastructure (houses, buildings, bridges), and agricultural land to flood plains further amplified the destructive effects. Although atmospheric thermodynamic and dynamic processes were used to describe this exceptional rainfall event, there was no mention of how climate change may have contributed to it. We show that the probability of this brief and powerful event occurring without human-caused climate change were incredibly low. Our research aims to demonstrate how climate change may have affected the likelihood that this extreme rainfall event will occur as well as to outline the difficulties in doing so. This was accomplished using the methods recommended by the World Weather Attribution (WWA) group. We examine whether and how much human-caused climate change has affected the likelihood and intensity of the rainfall over the Balkans as well as the peak 5-day precipitation in order to achieve this. We consider both historical weather data and climate models with and without anthropogenic forcing. The findings suggested that one of the key elements in determining event likelihood calculations is domain selection. Given the current situation and the possibility for further excessive rainfall over the Balkans, it is critical to enhance water management and lessen vulnerability to extreme rainfall. Acknowledgement:This research was supported by ExtremeClimTwin project, which has received funding from theEuropean Union’s Horizon 2020 research and innovation programme under grant agreement No 952384.