In Rwanda, the annual commemorations of the genocide are associated with an increase in the level of collective traumatic crises whereby many people participating in commemoration activities present various symptoms, including emotional distress and re-experiencing traumatic events of the 1994 genocide. These sudden crises normally last between 30 and 120 minutes and can affect hundreds of people at big commemoration events. They are accompanied by a degree of urgency that disturbs the whole assembly. This article briefly presents an overview of these crises and highlights the results of a study on the effects of a supportive-expression group intervention in the post-crisis period for people who experienced these collective traumatic crises. The study compares the therapeutic progress made by a group of people who participated in a supportive-expression group therapy program as compared to those who did not receive the intervention. The study suggests that the supportive group intervention can improve the overall psychological wellbeing of people who experienced collective traumatic crisis even though it was ineffective for some symptoms.