title: Flash floods in the Tatra Mountain streams: frequency and triggers.
abstract: Flash floods represent a frequently recurring natural phenomenon in the Tatra Mountains. On the northern slopes of the mountain chain, located in Poland, ongoing and expected future changes in climate are thought to further increase the adverse impacts of flash floods. Despite the repeat occurrence of major floods in the densely populated foothills of the Polish Tatras, the headwaters have been characterized by a surprising lack of data, such that any analysis of process variability or hydrometeorological triggers has been largely hampered so far. In this study, dendrogeomorphic techniques have been employed in four poorly-gauged torrential streams of the northern slope of the Tatra Mountains to reconstruct temporal and spatial patterns of past events. Using more than 1100 increment cores of trees injured by past flash floods, we reconstruct 47 events covering the last 148 years and discuss synoptic situations leading to the triggering of flash floods with the existing meteorological and flow gauge data. Tree-ring analyses have allowed highlighting the seasonality of events, providing new insights about potential hydrometeorological triggers as well as a differentiating flash flood activity between catchments. Results of this study could be useful to design future strategies to deal with flash flood risks at the foothills of the Polish Tatras and in the Vistula River catchment.
authors.affiliation: Dendrolab.ch, Institute of Geological Sciences, University of Berne, 3012 Berne, Switzerland; Climatic Change and Climate Impacts, Institute for Environmental Sciences, University of Geneva, 1227 Carouge, Switzerland. Electronic address: juan.ballesteros@dendrolab.ch.
authors.forename: J A
authors.initials: JA
authors.lastname: Ballesteros-Cánovas
authors.affiliation: Faculty of Earth Sciences, University of Silesia, Poland.
authors.forename: B
authors.initials: B
authors.lastname: Czajka
authors.affiliation: Faculty of Earth Sciences, University of Silesia, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Janecka
authors.affiliation: Faculty of Earth Sciences, University of Silesia, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Lempa
authors.affiliation: Faculty of Earth Sciences, University of Silesia, Poland.
authors.forename: R J
authors.initials: RJ
authors.lastname: Kaczka
authors.affiliation: Dendrolab.ch, Institute of Geological Sciences, University of Berne, 3012 Berne, Switzerland; Climatic Change and Climate Impacts, Institute for Environmental Sciences, University of Geneva, 1227 Carouge, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Stoffel
keywords: Dendrogeomorphology; Hydrometeorological triggers; Norway spruce; Paleohydrology; Poland; Tatra Mountains