The aim of EFAS is to gain time for preparedness measures before major flood events strike particularly for trans-national river basins both in the Member States as well as on European level.
In 2011 EFAS became part of the Emergency Management Service of the COPERNICUS Initial Operations[6] and in support to European Civil Protection.
It provides probabilistic, flood early warning information up to 10 days in advance to its partners – the National Hydrological Services and the European Response and Coordination Centre (ERCC).
The Central European flood event of June 2013 was the first big scale crisis during which the operational EFAS was actively reporting to the ERCC.
[17] The European Environmental Agency estimated that floods in Europe between 1998 and 2002 caused about 700 deaths, the displacement of about half a million people and at least 25 billion Euros in insured economic losses (EEA, 2003).
EFAS is part of a strategy for improved disaster management in Europe to reduce the impact of transnational floods through early warning.
First of all, the aim of the system is to provide, useful, complementary and shared information on upcoming flood events to the national hydrological services.
Since the hydrological model was set up for EFFS on European scale and the Deutscher Wetterdienst[12] agreed to provide real-time weather forecasting data to the JRC during the event, the EFFS experimental set-up could be used to simulate the ongoing floods and how the flood waves could be expected to travel down the Danube river.
Furthermore, Austria, Czech Republic, Germany, Hungary, and Slovakia detached experts to assist the JRC with the building of such a system.
The Deutscher Wetterdienst agreed to continue providing the JRC with historic and real time weather forecasts for setting up and testing of EFAS.
In order to capture the possibility for extreme events correctly, ensemble prediction systems have been designed[21] and multi-model approaches are desirable.
2005: An emerging European system for forecasting floods was viewed critically by the Member States as conflicting information to civil protection from different sources could lead to confusion and thus be counter-productive.
Since the EFAS network was still patchy, individual reports needed to be drafted for each partner on a daily basis, updates provided etc.
2009-2012: During this time the JRC participated in an FP7 project called IMPRINTS[26] on the development of an early warning indicator for flash floods.
The teams onsite could follow online the flood situation with an outlook for the coming days also for the neighbouring countries on one interface displaying comparable information, harmonised colour codes, English language, etc.
Since the last 10 years, however, the hydrological community is looking increasingly at the use of ensemble prediction systems (EPS) instead of single (deterministic) forecasts for flood warning times beyond 48 hours.
The trend for implementing hydrological ensemble prediction systems in operational flood forecasting centres can clearly be seen in Europe,.
Its forecasts are based on two deterministic, medium-range forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF) and the German Weather Service (DWD), (and thus different models) and on two sets of EPS: One from ECMWF which covers the medium-range up to 15 days globally (with a spatial resolution of ~30 km and 51 members, and one from the Consortium for Small-scale Modeling (COSMO), a limited area model EPS covering most of Europe with a shorter range up to 5 days (with a spatial resolution of 7 km and 16 members).
[35] In a case study it has been demonstrated that using the eight global medium-range EPS available worldwide can provide a higher reliability for the results,[36] but is computationally intensive.
Instead, based on observed meteorological data, long-term discharge time series are calculated at each grid with the same LISFLOOD model parameterisation that is set up in the forecasting system.
It is an international research initiative with the aim to "demonstrate the added value of hydrological ensemble predictions (HEPS) for emergency management and water resources sectors to make decisions that have important consequences for economy, public health and safety."
HEPEX is organised around six major themes, i) Input and pre-processing, ii) Ensemble techniques and process modelling, iii) Data assimilation, iv) Post-processing, v) Verification and vi) Communication and use in decision making.