Debris-flow activity in the Alps is anticipated to undergo pronounced changes in response to a warming climate. Yet, a fundamental challenge in comprehensively assessing changes in process activity is the systematic lack of long-term observational debris-flow records. Here, we reconstruct the longest, continuous time series (1626-2020) of debris flows at Multetta, a supply-limited torrential system in the Eastern Swiss Alps.
View Article and Find Full Text PDFThe primary goal of paleoflood hydrology is to estimate the frequency and magnitude of past floods. Botanical evidence, and particularly scars on trees, has been used repeatedly as paleostage indicators to reconstruct peak discharges and flood height. Yet, these reconstructions depend on the presence of visible scars on tree stems which tend to be masked as trees grow older.
View Article and Find Full Text PDFIn the current context of anthropogenic global warming, one of the purposes of dendrogeomorphic analyses is to provide long and continuous chronologies of mass movements, so as to detect potential trends or shift related to increasing temperatures. However, on documented slopes, the comparison between historical archives and tree-ring records suggests that dendrogeomorphic reconstructions systematically underestimate the natural activity of the process under investigation. In the specific case of snow avalanches, underestimation generally amounts to 50% and the main causes generally given for this difference are related to the magnitude of past events.
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