Heavy rain and floods in Rhineland-Palatinate in May/June 2016

10 08 2016

Water level prediction in small river catchments is still a challenge

In parts of Rhineland-Palatinate, heavy  rainfall of 200-300 mm occurred between May 27th and June 26th 2016. This amount is about 3 to 4 times the amount of an average precipitation in the month June.  Many heavy  rainfall events have been measured,  that normally  occur once in 100 years.  Consequences were local floodings, torrents and land slides. The highest radar measurement was an amount of 115 mm in 2 hours on the 4th of June in the municipality  of Grafschaft/Ahrweiler, where  a retention basin designed on extreme events was overflown.
Besides local floodings along the smaller river bog floods occurred. Especially,  along the river Ahr big damages happened, where in the morning hours of June 2nd, a century flood affected large areas. All flood events were caused by a series of several heavy rainfall events. The exact forecast of heavy rainfall per village  and of the expected amount is still not easy for the weather alarm authorities and was on the border of reachability. The water level forecast for the smaller rivers still is a challenge, due to the short time left before the event  occurred  of only 6-12 hours and the width of the water level development based on 21 ensemble  calculations. The full report (in German language) is downloadable at: http://www.hochwasser-rlp.de/publikationen/bericht_starkregen_hochwasser_juni2016.pdf