We invite all hydroclimatic researchers to submit the results of their studies to a special issue of Natural Hazards and Earth System Sciences (NHESS) addressing the theme of hydroclimatic extremes and impacts at catchment to regional scales. Please find the instructions for authors on the NHESS web page. The individual papers will be peer-reviewed and published as soon as they are available in regular issues but will be labelled as part of the special issue and linked electronically. The main purpose of the special issue is to focus on hydroclimatic extremes (floods and droughts) at catchment and regional scales and their impacts on a broad range of hydrological and environmental systems, including mitigation approaches. Nevertheless, broad topics around hydroclimatic extremes (e.g. temporal variability and trends, atmospheric mechanisms, propagation throughout the hydrological cycle, hydrological modelling of extremes) and the impact of climate change on hydroclimatic extremes are also encouraged. The special issue was inspired by the Water-JPI IMDROFLOOD project but submissions from all researchers working on suitable topics are welcome, even if they are not participating in the project. In fact, all scientists working on this topic should feel able to contribute. Therefore, please forward this call for papers to your colleagues.