1 What made the June 2013 flood in Germany an exceptional 2 event? A hydro-meteorological evaluation 3 4 Kai Schröter1,3, Michael Kunz2,3, Florian Elmer1,3, Bernhard Mühr2,3, Bruno 5 Merz1,3 6 [1]{Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 7 Hydrology, Potsdam, Germany} 8 [2]{Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, 9 Karlsruhe, Germany} 10 [3]{CEDIM – Center for Disaster Management and Risk Reduction Technology, Germany} 11 Correspondence to: K. Schröter (
[email protected]) 12 13 Abstract 14 The summer flood 2013 sets a new record for large-scale floods in Germany for at least the 15 last sixty years. In this paper we analyze the key hydro-meteorological factors using extreme 16 value statistics as well as aggregated severity indices. For the long-term classification of the 17 recent flood we draw comparisons to a set of past large-scale flood events in Germany, 18 notably the high impact summer floods from August 2002 and July 1954. Our analysis shows 19 that the combination of extreme initial wetness at the national scale - caused by a pronounced 20 precipitation anomaly in the month of May 2013 - and strong, but not extraordinary event 21 precipitation were the key drivers for this exceptional flood event. This provides additional 22 insights into the importance of catchment wetness for high return period floods on a large- 23 scale. The data base compiled and the methodological developments provide a consistent 24 framework for the rapid evaluation of future floods. 25 1 Introduction 26 In June 2013, wide parts of Central Europe were hit by large‑scale flooding.