HyMeX – Advances in understanding and forecasting of heavy precipitation and flash floods in the Mediterranean. The HyMeX international research project (Hydrological cycle in the Mediterranean eXperiment, www.hymex.org), as part of the multi-agency MISTRALS program launched in 2010 for a 10-y period, aims at advancing our understanding of the water cycle in the Mediterranean, and in particular to improve knowledge and forecasting of hydrometeorological risks. At the heart of the HyMeX project, are the study and forecasting of heavy precipitation and flash flood events that regularly affect the Mediterranean region. After a presentation of the general observation strategy which combined research field campaigns, reinforcement of observation...