Аннотация:Several historical case studies of the powerful outburst floods caused by catastrophic breachof large rockslide dams are described. Such phenomena could result in the cross-border disasters if the breaching dam is located in one country and the affected river flows to the another one. Additional information about characteristics of such events can be derived from the study of the similar prehistoric outburst floods. Measures that help mitigating the most adverse effects of such phenomenaare discussed.