Debris flows in Val Parma and Val Baganza (Northern Apennienes) during the 13 October 2014 alluvial event in Parma province (Italy)

Abstract

During the 13 October 2014 rainstorm event that affected the Val Parma and Val Baganza area, several debris flows affected the Mt. Cervellino relief (northern Apennines, Italy), causing severe and widespread damages to check-dams, roads and other infrastructures. Such event, together with the Piacenza province event of 2015, has generated the perception of debris flows as a breaking new potential cause of widespread damages in the Emilia-Romagna. The meteorological event of October 2014, reconstructed by means of rain gauges and radar data, reached intensities as high as 80 mm/hour, which is well above any debris flow triggering thresholds presented in literature. However, data show that debris flows have occurred in any location where 30 mm/hour were exceeded. The result was the occurrence of tens of debris flows, which were triggered in zones of failure of slope debris coverage along the streams, and that remobilized and scoured debris along the track and destroyed several check dams and damaged roads that were overflown by debris. This paper is aimed to document the distribution and characteristics of the debris flow events that occurred during such event. By doing so, it also warns against this potentially destructive events that, in a changing meteorological framework, might result much more frequent and widespread than expected also in the northern Apennines.