Estimation of debris flood magnitudes based on dendrogeomorphic data and semi-empirical relationships

Evidence for enhanced debris-flow activity in the Northern Calcareous Alps since the 1980s (Plansee, Austria)

“…9 show an increase of absolute and annual debris-flow volumes and an enhanced frequency since the 1980s on all eight fans. Analogous results, with event peaks between the years 1990 and 2000, are documented in other parts of the European Alps (Procter et al, 2011;Pavlova et al, 2014;Schraml et al, 2013). Bollschweiler and Stoffel (2010b) show in the Zermatt valley also an increase since 1950 until 2000 and a following reduction of debris-flow activity until today using dendrogeomorphological analysis.…”

“…The slope of the fan γ d was determined by using the highest point of the fan and a point at road level, as specific information for the deepest point below water surface of the Plansee were not available. The slope of the torrent γ c was defined by a point in the catchment, at which a channelised flow could be firstly observed, and the lowest point of the fan (Schraml et al, 2013). For an error calculation the slopes of both fans and channels were varied by ±3°in each time interval.…”

“…For dating debris flows on larger time scales, 14 C dating of organic matter involved in the process is applied (Matthews et al, 2009) and rarely 3 He (Cerling et al, 1999). For more recent debris flows, growth disturbances in century-old trees (Bollschweiler et al, 2007;Stoffel et al, 2008;Bollschweiler and Stoffel, 2010a;Stoffel, 2010;Saez et al, 2011;Schraml et al, 2013), orthophoto reconnaissance (Lang et al, 1999;Helsen et al, 2002;Procter et al, 2011Procter et al, , 2012D'Agostino, 2013) or lichenometric dating is applied (Winchester and Harrison, 1994;Helsen et al, 2002). However, most of these studies rather target debris-flow recurrence rates, whereas this study quantifies the volume of mean annual debris-flow transport and compares it on different time scales.…”

Unravelling past flash flood activity in a forested mountain catchment of the Spanish Central System

“…Baker, 1987;Hupp, 1988), tree rings have been used much less frequently as compared to other lines of evidence of paleofloods (e.g., slackwater deposits; Benito and Thorndycraft, 2004). The large potential of dendrogeomorphic tools for the assessment of frequency and magnitude of past events has been demonstrated in recent works (e.g., Ballesteros et al, 2011;Gottesfeld and Gottesfeld, 1990;Gottesfeld, 1996;Ruiz-Villanueva et al, 2010;Schraml et al, 2013;St. George and Nielsen, 2003).…”

Tree-ring based record of intra-eruptive lahar activity: Axaltzintle valley, Malinche volcano, Mexico

“…Dendrogeomorphic techniques have been used widely to reconstruct hydrogeomorphic process activity (Stoffel and Wilford, 2012;Ballesteros-Cánovas et al, 2015a). The past focus was clearly on debris flows in the European Alps for which the frequency (Arbellay et al, 2010a(Arbellay et al, , 2010b, magnitudefrequency relationships (Stoffel, 2010;Schraml et al, 2013), spread and reach (Bollschweiler et al, 2007(Bollschweiler et al, , 2008aStoffel, 2008;, regional patterns (Procter et al, 2012Schraml et al, 2015, triggers (e.g., Lugon and Stoffel, 2010;Stoffel et al, 2011a;Schneuwly-Bollschweiler and Stoffel, 2012) and potential future evolutions (Stoffel and Beniston, 2006;Stoffel et al, 2014aStoffel et al, , 2014b have been documented in detail with tree-ring series.…”