• informing the authorities in the Member States of the possibility of a flood to happen before the local systems capture the event with their own monitoring and forecasting systems;
• providing catchment based information that gives downstream authorities an overview of the current and forecasted flood situation also in upstream countries. This does not only include the immediate upstream country but also any further potentially useful upstream information.
EFAS provides medium-term (3 to 10 days) flood forecasts, based on different meteorological inputs, as complementary information to the typical short-term (less than 48 hours) forecasts performed by national centres. The challenge of EFAS is to combine all hydrographs, calculated from different mediumrange weather forecasts, into one early flood warning information that is useful for local flood forecasting centres. EFAS information is disseminated to
the EFAS users in the form of EFAS Information Reports, which summarise the situation in a concise way with spatial and temporal information.
The establishment of an EFAS network was initiated in August 2004, with a formal agreement between the JRC EFAS activity and ECMWF (meteorological data provider). In the agreement, about 30 hydrological services were identified as potential partner organisations. They were contacted in January 2005 with a Memorandum of Understanding (MoU) which identified the rules of collaboration for the EFAS research activity. The first MoU was signed in May 2005. Once EFAS could demonstrate its potential benefit during the summer floods in 2005, more authorities have joined the network, which comprises currently 22 authorities. Figure 1.1 shows the status of the river basin areas covered by EFAS MoU agreements on 26th June 2006.
At the moment, the crucial question for further development of EFAS is: does EFAS information actually help the receiving authorities to be better prepared for an oncoming flood event? To answer this question it is first necessary to discuss the potential benefits and limitations of EFAS forecasts for increasing preparedness for flood events.