Enhancing European Flash Flood Hazard iden4fica4on capaci4es Peter Salamon (JRC)
Enhancing European Flash Flood Hazard identification capacities The EFAS experience Peter Salamon DG JRC, Climate Risk Management Unit Brussels, 25.06.2015
The European Flood Awareness System Main aim: added value, transnational, medium range (2-10 days) flood forecasts to the national hydro-meteorological authorities and the ERCC for a better preparedness and improved disaster risk management in Europe. «EFAS is fully operational under Copernicus Emergency Management Service since Sep 2012 «Currently more than 40 partners For further info: www.efas.eu 3
Flash flood prediction at a European scale Many flash flood EWS are rain gauge or radar based Ø Warning lead times are thus very short (hours) How can we improve flash flood warning lead times? Can we develop a system applicable at European scale? Gardon d Anduze at Anduze High correlation for highflow conditions in small size catchments 4
The European Precipitation Index Climatology (EPIC) Using high resolution numerical weather predictions to build an indicator for upcoming extreme precipitation events and possible associated flash floods: The European Precipitation Index based on simulated Climatology (EPIC) EPIC compares accumulated upstream precipitation for durations up to 24 hours at each forecast time step with reference thresholds derived from a long-term reforecasts dataset 5
The European Precipitation Index Climatology (EPIC) EPIC technical details: «Based on high-resolution COSMO-LEPS forecasts (16 members, 3 hourly timestep, 7km res., 5 days leadtime) «thresholds derived from a 20-year climatology «Drainage network at 1 km resolution «Fit for catchments with area between 50 km2 and 2000 km2 «EPIC probabilities are considered for the lead time range 12 120 hours «EPIC provides only affected areas, not the detailed locations 6 Alfieri, L. and Thielen, J. (2015), A European precipitation index for extreme rain-storm and flash flood early warning. Met. Apps, 22: 3 13. doi: 10.1002/met.1328
Operational flash flood warning in EFAS «EFAS flash flood warnings based on EPIC since October 2013 «Average warning lead time 32 hours (effective lead time approx. 24 hours) «EPIC skill scores (Dec 2009 Nov 2010): hit ratio 0.89 ; threat score 0.34 «Includes landslide susceptibility 7
From EPIC to ERIC: from precipitation to runoff Problems of EPIC: «No separation between rain and snow «No accounting for hydrological (soil moisture) and geomorphological (slope, landuse) conditions Functioning: q Separation rain and snow q Introduction of the runoff coefficient Daily initial soil moisture f r o m LISFLOOD model Runoff/soil moisture relationship from the LISFLOOD soil moisture climatology on a 5x5km² grid spacing Daily runoff map used to weight the u p s t r e a m precipitation 8
From EPIC to ERIC: from precipitation to runoff ERIC is currently being tested for operational integration into EFAS: «Operational release foreseen September/October 2015 «ERIC skill scores: hit ratio 0.59 threat score: 0.5 Raynaud, D., Thielen, J., Salamon, P., Burek, P., Anquetin, S. and Alfieri, L. (2014), A dynamic runoff co-efficient to improve flash flood early warning in Europe: evaluation on the 2013 central European floods in Germany. Met. Apps. doi: 10.1002/met.1469 9
Flash flood identification in EFAS: an outlook «««Testing of selected EDHIT nowcasting products in EFAS Seamless integration of gauge observations, nowcasting and weather forecasts to improve flash flood warnings Real time impact assessments 10