## 6 Conclusions  
Debris flow events potentially affecting the Croso stream basin, could be triggered by different kind of meteorological events: prolonged rainfalls episode (i.e., October 2000) or intense and concentrated rainfalls (i.e., August 2019). Despite this, debris flows are characterised by a similar magnitude. The meteorological conditions were computed using WRF model at high horizontal and vertical resolution, in order to capture local phenomena occurring in very complex terrains. The proposed set-up of WRF was able to predict sufficiently well the total precipitation accumulated in the two events, with better performances during the October 2000 event, when floods affected the Piedmont region, and in general the Po plain area. Instead, in August 2019, the total amount of precipitation was in general underestimated by 20 to 50 per cent.  
On the other side, in both cases, the timing of the precipitation was correctly predicted by WRF and this aspect reveals the trustworthiness of the actual WRF set-up, that lack only in the intensity of convective processes, but not in the triggering phenomena of precipitation events. The low simulated quantity of precipitation during the August 2019 convective events was probably due to the microphysics scheme adopted (single moment, WSM-6), and probably a double moment scheme could enhance the total amount in case of shallow and deep convection.  
The WRF model here applied to a complex slope considering the different kinds of landslides affecting it (Figure 2), has been already applied in the same set-up in different complex mountain terrains [24] and could be adopted to produce the meteorological fields for and a hydrological model that could give an insight into the link between debris flows and precipitation triggering. Moreover, the application of the data coming from the applied WRF model, set with the tested parameters, specific for this kind of terrain, could be an aid within the early warning procedures related to the incoming possibility of specific meteorological events potentially triggering instability events in sensitive areas, like the analysed hydrographic basin. In this context, geological and geomorphological analyses and maps [40] surely contribute to improving knowledge useful to understand the environmental responses to heavy rains better (e.g., rainfall thresholds triggering debris flows; [23; 59]) and to investigate hazard and risk scenarios. Moreover, reliable meteorological conditions forecast, together with simplified geomorphological maps and sketches (e.g., Geobox, [2]), could help in spreading knowledge for local management purposes, favouring practices of usable science aimed at mitigating risk scenarios [60].  
**Author Contributions:** Conceptualisation, A.G., I.M.B., M.P., and S.F.; methodology, A.G., I.M.B., and S.F.; software, A.G.; validation, A.G., I.M.B., M.L., and S.F.; formal analysis, A.G.; investigation, A.G., I.M.B., M.L., M.P., and S.F.; data curation, A.G., I.M.B., and M.L.; writing--original draft preparation, A.G., I.M.B., M.L., M.P., and S.F.; writing--review and editing, A.G., I.M.B., M.L., M.P.[PERSON] and S.F.; visualisation, A.G. and I.M.B.; project administration, M.P.; funding [PERSON], S.F., M.P., and I.B. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research is part of the METALP Project, funded by Fondazione CRT, grant 2019.0455; Fondi Potenziamento della Ricerca, Universita degli Studi di Milano, linea 2, 2018-2019 (entrusted to [PERSON]).  
**Acknowledgments:** The weather station data are retrieved from the ARPA Piemonte weather network database (ANTARES) under the agreement between the University of Turin, department of Physics. Authors are also thankful to Ente di Gestione delle Aree Protette dell'Ossola, Municipality of Varzo, [PERSON] and [PERSON] supporting the installation of the Alpe Veglia weather station.  
**Conflicts of Interest:** The authors declare no conflict of interest.