Since a few decades different zones along the open, sandy macrotidal Belgian coast show a residual erosional beach evolution. Classic coastal defense structures have only proved to be useful by impeding further retreat of the dunefoot. Lowering of the beach itself still goes on. Carrying out beach profiles, the author describes the course of the phenomenon in the Bredene - De Haan zone. Using successive beach profilings at the representative station Klemskerke KP 38 during the period 1976-1979, he studies the short run evolution of transversal sand mobility and beach budget and puts forward that the erosional attack belongs to a cyclic, repetitive and alternating coastal megaprotuberance. Evidence for its nature is given by historical arguments