EU Science Hub

HEPEX 10th Anniversary Workshop

Jul 01 2014

The 10th anniversary workshop of the HEPEX (Hydrological Ensemble Prediction Experiment) initiative was hosted by the National Oceanic and Atmospheric Administration (NOAA) in Maryland, USA from 24-26 June 2014.

More than 70 scientists came together in the impressive new National Center for Environmental Prediction (NCEP) to listen to lectures on state-of-the-art techniques and uses of ensemble predictions for floods, droughts and water resource management. A further 30 followed the meeting online, via a webcast and twitter. The experiences of scientists and end users from a number of countries, including the US, Canada,  Europe, China, Korea, India and Australia, were shared during lectures, poster sessions, break-out groups, discussions and practical sessions with games about decision-making in the face of uncertain predictions.

The workshop looked at

  • what has been achieved in a decade of hydrological probabilistic forecasting,
  • how we have learned to cope with the wealth of meteorological and hydrological data and which gaps still exist, and
  • how probabilistic information can be produced and communicated in a way that effectively helps decision makers to take the best decision – key in effective water and emergency management.  

Recent projects such as the Commission’s European Flood Awareness System (EFAS) and the US National Weather Service’s Hydrologic Ensemble Forecast System (HEFS) have greatly benefited from the strong interaction with the HEPEX community to find unique and novel solutions to community-wide challenges in hydrologic forecasting.

Key messages that resulted from the workshop include:

  1. skill in probabilistic forecasts has improved considerably, but expertise is still needed in converting knowledge into decisions;
  2. ensemble forecasts inform risk-based decision making, but it is important to get more involvement of all actors in the probabilistic forecasting chain;
  3. learn by doing: training is a real opportunity for forecasters and end users to improve the uptake of ensemble predictions in advanced operational hydrological forecasting systems.


HEPEX was sparked off in 2004 by research in the USA and Europe, and notably by projects such as the “European Flood Forecasting System” (EFFS) project (FP5, 1999-2002) where for the first time in Europe the benefits of meteorological ensemble prediction systems were explored for flood forecasting. Chaired originally by representatives of NOAA and the European Centre for Medium-Range Weather Forecasts (ECMWF), with additions from the JRC in 2007 and the National Center for Atmospheric Research (NCAR) in 2013, HEPEX has developed into a broad network of enthusiastic and devoted scientists, forecasting groups, and end users who share their knowledge during meetings and workshops as well as through a modern blog-driven website, webinars and web interviews. Its central aim is to promote the added value of hydrological ensemble predictions (HEPS) for the emergency management and water resource sectors to make decisions that have important consequences for the economy, public health and safety.

The meeting was co-organised by the host agency (NOAA) and HEPEX co-chairs with additional support and sponsorship from the French National Research Institute of Science and Technology for Environment and Agriculture (IRSTEA) and the Dutch research institute Deltares, and guidance from a multi-institution planning committee. More information about the Workshop and HEPEX can be found online at http:/

Further information