Three different series of events, the EGU Leonardo Conference, held every year in Europe, the IAHS Statistical Hydrology (STAHY) Workshop, held every year in different places of the world, and the Hydrofractals Conference, held every ten years, coincide in space and time: Kos Island, Greece, 17–19 October 2013. Each of these events has its own dynamics but all three have been set to focus on a common idea: the uncertainty in natural processes.