On 22 October 2019, the Francolí river basin (Catalonia, Spain) experienced a heavy precipitation event, resulting in a catastrophic flash flood. The main hydrometeorological factors are investigated. The social response times are also collected and compared with catchment dynamics in order to examine the adequacy of monitoring and warning issuance. Finally, the study provides recommendations aimed at minimizing losses and improving preparedness for similar natural hazards in the future.

On 12 and 13 September 2019, a long-lasting heavy precipitation episode resulted in widespread flash flooding over eastern Spain. Well-organized and quasi-stationary convective structures impacted a vast area with rainfall amounts over 200 mm. The very dry initial soil moisture conditions resulted in a dampened hydrological response: until runoff thresholds were exceeded, infiltration-excess generation did not start. This threshold-based behaviour is explored through simple scaling theory.

This is a collective effort to describe the state of the art in Mediterranean cyclone dynamics, climatology, prediction (weather and climate scales) and impacts. More than that, the paper focuses on the future directions of research that would advance the broader field of Mediterranean cyclones as a whole. Thereby, we propose interdisciplinary cooperation and additional modelling and forecasting strategies, and we highlight the need for new impact-oriented approaches to climate prediction.

Previous evaluation of rainfall estimation by satellite algorithms showed an insufficient over Northern Tunisia. That was why we tried the WRF. We selected four heavy rainy days. For each day, 99 combinations of Cu and PBL are simulated. The sensitivity study highlighted the large difference in the estimation by the different schemes. The use of several verification techniques was extremely helpful to choose the best combinations for each event. The ensemble method gave very satisfying results.

The performances of flash-flood forecasts are evaluated using a meteorological model forcing a rainfall-runoff model. Both deterministic (single forecast of the most likely weather) and ensemble forecasts (set or ensemble of forecasts) have been produced on three subcatchments of the eastern Pyrenees exhibiting different rainfall regimes. Results show that both overall discharge forecast and flood warning are improved by the ensemble strategies with respect to the deterministic forecast.