Nowcasting and impact-basEd PredicTions of inUndations in mediterraNean catchmEnts

2026-07-22

Fatalities and economic damages from short-lived precipitation extremes along the Mediterranean coasts leading to flash floods (FF) take a considerable share of the flood impacts, and of all weather related hazards in general. Their damaging potential is particularly strong due to their sudden onset, fast development, destructive power and poor forecasting skills. Physically-based modelling chains to predict FF impacts suffer from large uncertainties which often prevent from skillful predictions in the different modelling steps. A recent example of trans-border disaster in Europe is that of the storm Alex, in october 2020. This extra-tropical cyclone severely affected Mediterranean region between France and Italy. Among impacted catchments, the Roya watershed is a particularly interesting example to analyse, being a transboundary river basin prone to FF, hence where fast and effective cross-border collaboration is key to improve disaster risk reduction. In this context, the main goal of the NEPTUNE project is to develop flood forecasting tools that can be used in trans-border areas as well as more generally over Mediterranean areas prone to flash floods (FF). Those methods will be tested on the trans-border Roya catchment, regularly affected by flash floods. On this catchment, the NEPTUNE project aims at: • improving precipitation estimates, especially on the upper part of the catchment, at present poorly covered by weather radars; • improving both weather and hydrological forecasts at small spatio-temporal scale; • developing an impact-based model for real-time information on flood risks rather than only hazards; • better disseminating information across all French an Italian actors involved.

France

2025-12-15