Hydrological extremes are strongly impacted by climate change and represent one of the most relevant and hard-to-predict hazards over the Italian territory. The evaluation of the effectiveness of adaptation actions for water-related hazards requires actionable information about climate change and future hazards. Current methodologies based on multi-model downscaled climate projections are challenged by high uncertainty and large model bias. To deal with such uncertainty, event-based storylines have been proposed as a complementary approach that is much more tailored around stakeholders' needs. The storylines describe plausible unfolding of extreme events, based on realistic simulations and an end-to-end description linking physical drivers to regional impacts. In this direction, recently developed weather and climate predictions provide unprecedented high-resolution large-ensemble numerical simulations to develop large catalogues of extreme events that can complement the short observational series and support storylines via the identification of unseen weather extremes.