Damage of a dike may result in severe damage and suffering. To reduce downstream damage and loss of life, it is important to study the process of breaching of the damaged dike. It is not possible to understand the damage process without a clear understanding of the flow patterns encountered. In the present study, data obtained from nine experimental runs are analyzed. The flow patterns and progressive damage of dike overtopping are investigated. Two types of phenomena at the dike surface: erosion; and erosion and sliding, are observed during the overtopping event. Four stages of dike damage can be distinguished. The degradation rate of the dike crest is found to be dependent on the downstream slope of the dike. The degradation rate is higher when the downstream slope is steeper. Damage is a possible cause in severe damage and suffering. To reduce downstream damage and loss of life, it is important to study the process of breaching of the damaged dike. It is not possible to understand the damage process without a clear understanding of the The flow patterns and progressive damage of dike overtopping are investigated. Two types of phenomena at the dike surface: erosion; and erosion and sliding, are observed during the The degradation rate of the dike crest is found to be dependent on the downstream slope of the dike. The degradation rate is higher when the downstream slope is steeper.