Construction of dams on streams allows multiple beneficial uses to the population. But in the advent of extreme floods, the structures may fail and free the stored water. Recently built structures respond to more and more demanding design standards. Older structures, which were deemed safe at the time of their construction, might sometimes no longer satisfy these new standards. To evaluate the necessity, the importance and the urgency of works that would make these structures conform again, one of the more and more used approaches consists in resorting to a risk analysis. A risk analysis has been applied a posteriori on a site where a failure was observed in order to determine whether this approach would have brought the managers to undertake corrective works. This application shows the limited capacity of the conventional risk analysis for dams. Two alternative approaches are presented and discussed as a tool to evaluate the risk of a site.Key words: risk analysis, dam break, dam, public safety.[Journal translation]