Abstract
High-impact precipitation events (HIPEs) in mountainous regions are frequently associated with severe flooding, landslides, and significant impacts on infrastructure and human safety. However, a comprehensive understanding of their spatio-temporal distribution and underlying atmospheric drivers across the European Alps is still lacking. In this study, we identified and ranked over 1,000 HIPEs based on their intensity and spatial extent using a multi-source daily precipitation data set for the Alps covering the period 1961–2022. We analyzed their seasonal characteristics, geographic distribution, and link to flood events based on flood impact data from the HANZE (Historical Analysis of Natural HaZards) database. Furthermore, we applied a synoptic classification to identify the main weather types and quantify their contribution to HIPE occurrence. Our results revealed strong seasonal and spatial variability. The most widespread and intense events occur in autumn over the southern Alps. In contrast, the more frequent but localized summer HIPEs tend to be concentrated over the northern Alps. Synoptic patterns associated with Mediterranean moisture transport and orographic lifting account for the most impactful events, many of which coincide with major historical floods on the southern flank of the Alps. The database of HIPEs and their characterization represent unique resources for advancing impact-based forecasting and regional risk assessments in the Alps.