The European Flood Alert System: Early Flood Warning Based on Ensemble Prediction System Products

Over the last decades several severe floods with a trans-national dimension have taken place in Europe. 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). In 2005 wide spread and repeated flooding was again observed in several tributaries to the Danube river basin, particularly in Switzerland and Austria as well as in the lower Danube countries such as Romania and Bulgaria. And only one year later, in spring 2006, record floods hit again the Elbe and Danube. The European Flood Alert System (EFAS) addresses floods on European scale by increasing preparedness for large floods from the typical 1-3 days to 4-10 days. Drawing experience from previous research results (Gouweleeuw et al., 2005), the project started in 2003 with the development of a prototype which is being built at the European Commission Joint Research Centre (JRC) in close collaboration with the national hydrological and meteorological services. EFAS information are distributed to flood experts and not the general public. In EFAS the longer flood warning times are achieved by incorporating medium-range weather ensemble forecasts into the flood predictions. Although by definition probabilistic information is associated with uncertainty - and the longer the leadtimes the higher the uncertainty becomes -, the information is still beneficial for the hydrological services because they are aware that a certain possibility for a flood event in the near future exists. Such information can lead to the discussion of likely flood scenarios, adapting work schedules and enhanced monitoring of the meteorological and hydrological conditions over the coming days. Should subsequent forecasts not confirm the previous alert, the forecasting offices go back to business-as-usual routine. In the opposite case, however, the flood forecasters can start off with a better preparation and knowledge what to do and gain time when analysing their own short-term – and more precise – forecasts. The level of stress in the forecasting centres would be reduced. Research has shown that the negative effects of stress on decision making under time pressure and fatigue due to overwork in the operational centres during a flood event should not be underestimated (Kowaski-Trakofler et al., 2003, Paton and Flin 1999).

THIELEN DEL POZO Jutta;  BARTHOLMES Jens;  KALAS Milan;  DE ROO Arie; 

2007-11-30

OPOCE

JRC37684

https://publications.jrc.ec.europa.eu/repository/handle/JRC37684,