Intense rainstorms that release vast amounts of water within minutes and over very limited areas are becoming increasingly common in parts of Italy, placing rivers, slopes and drainage systems under mounting pressure. This trend emerges from a new meteorological reanalysis dataset analyzed in a study led by the University of Milan, funded by European resources and carried out in collaboration with the National Research Council of Italy, the Norwegian Meteorological Institute, and RSE S.p.A..
Published in the scientific journal Natural Hazards and Earth System Sciences, the research shows that in several Italian regions, episodes of extremely intense hourly rainfall have almost doubled compared to 35 years ago. The increase is particularly evident during summer and autumn, notably in the pre-Alpine areas between Piedmont and the Aosta Valley, across Lombardy and South Tyrol, as well as in parts of coastal Liguria, the Ionian Sea basin and Sardinia.
The rise in extreme precipitation events is consistent with global climate change trends. Warmer seas enhance evaporation, while a warmer atmosphere can retain more moisture and energy, creating conditions that favor heavy rainfall over very short time spans.
“These findings help deepen our understanding of how climate change is affecting extreme precipitation in Italy and provide valuable insights for civil protection policies, infrastructure resilience and future planning,” said Francesco Cavalleri, lead author of the study and a PhD in Environmental Sciences at the University of Milan.
The study also highlights the importance of combining traditional observational data with newer climate tools such as reanalysis datasets. “A broader use of these instruments is crucial to significantly improve risk assessments related to landslides, floods and other extreme hydrogeological hazards,” added Maurizio Maugeri, coordinator of the research project.