As advancing French and American forces prepared to cross the Rhine near Mulhouse in Eastern France, it was feared that the Germans would flood the Rhine valley by destroying the Kembs dam (barrage) which formed part of the hydro-electric system that also made the Rhine navigable.
Led by Wing Cdr 'Willie' Tait, 617 squadron took part in a daring daylight raid fielding a total of 13 Tallboy armed Lancasters. 7 bombing from 8000ft to distract the AA fire and 6 from below 1000ft to stand the best chance of a hit. 2 Lancs were lost but Tait's bomb fell right next to the dam and 30 minutes later a violent explosion breached the dam, the resulting loss of water leaving boats high and dry as far back as Basle in Switzerland.