Château Cugny is an exceptional place where the actual cliffs evolution is quite rapid. Because of the frost action, considerable quantities of frost-rived nibble broke off the cliffs each year. The relative frequency of rock falls enables measurements to be made with simple installations. Two examples of the daily freeze-thaw cycle show the variations of the rock falls during the day according to the temperature's changes. Frequent rock falls contribute to Château Cugny's cliffs rapid scarp retreat.<br> These rock falls occur by a 2-stage process: first, the frost susceptible lower portion of the cliff breaks apart resulting in undermining of the overlying non frostsusceptible portion which subsequently breaks off and falls down.