What made the June 2013 flood in Germany an exceptional event? A hydro-meteorological evaluation

Abstract

Abstract. The summer flood 2013 sets a new record for large-scale floods in Germany since at least 1952. In this paper we analyze the key hydro-meteorological factors using extreme value statistics as well as aggregated severity indices. For the long-term classification of the recent flood we draw comparisons to a set of past large-scale flood events in Germany, notably the high impact summer floods from August 2002 and July 1954. Our analysis shows that the combination of extreme initial wetness at the national scale – caused by a pronounced precipitation anomaly in the month of May 2013 – and strong, but not extraordinary event precipitation were the key drivers for this exceptional flood event. This provides new insights to the importance of antecedent soil moisture for high return period floods on a large-scale. The data base compiled and the methodological developments provide a consistent framework for the rapid evaluation of future floods.