It is shown that behavior of the multiple-bar system during a storm can be described in frameworks of the model assuming that bars move toward the sea with almost the same mean speed, while the over-bar depths increase in accordance with the local bed slope. Analysis of suspended-sediment balance over the bar crest leads to expression for the bar movement speed, which demonstrates very strong dependence on ratio of wave height to the over-bar depth. Using empirical criterion of bar activity the model suggested is capable assess the bar displacement during a storm action and predict the post-storm bed profile. Comparison with the published field data leads to conclusion that the computed and observed storm-induced deformations of barred beach slopes are in satisfactorily agreement.