The occurrence of extreme hydro-meteorological events is likely to increase in the future, essentially as a result of global change. Monitoring and forecasting flash-flood events remain challenging exercises – essentially due to the very flashy response of hydro-systems under exceptionally intense precipitation events, the inappropriate (i.e. coarse) design of conventional hydro-meteorological monitoring networks for this type of local events, and the focus of most forecasting models on large-scale riverine floods.While over the past decades progress has been made in precipitation monitoring (e.g. through weather radars), wireless sensor networks are increasingly seen as the next critical step in (extreme) hydro-meteorological forecasting. However, high energy consumption and limited connectivity in uneven terrain stand as major drawbacks in the roll-out of wireless networks based on conventional technologies, such as WiFi, or cellular networks. The recent advent of low-power wide-area networks (LPWAN) has brought additional momentum to a deployment and use of wireless sensor networks at unprecedented densities.Here, we propose to rely on the SIGFOX global IoT (Internet-of-Things) dedicated network – recently deployed in Luxembourg by project partner POST Telecom – for significantly improving at low cost the spatial representativeness of precipitation measurement protocols and the quality of hydrological forecasts. We hypothesize that LPWAN-enabled dense hydro-meteorological sensor networks will significantly reduce uncertainties in rainfall measurements, ultimately leading to substantially improved flash-flood forecasting capacities. We will rely on hydro-meteorological monitoring networks in two experimental catchments (Pétrusse & Ernz Blanche) in Luxembourg for testing our hypotheses.POST Telecom Luxembourg will participate in the design and crafting of LPWAN-enabled sensors – ultimately targeting a showcase for an application in environmental monitoring of its newly deployed LPWAN network. Having a direct interest in a new flash-flood forecasting tool, the Administration de la Gestion de l’Eau (AGE) will provide financial support to POST Telecom for the development of the LPWAN-enabled prototypes.