A classification system of catastrophic events is a methodology assembling all the catastrophe groups. There are many classifications of catastrophes. The most widely known are classified into: nature, consequences of the event, duration, affected territories and areas of the destroyed zone, and at last into the needed intervention measures. It is difficult to study the complexity of catastrophes with these classifications. We propose a new system of classifications of catastrophes based on “Complexity Criteria”. Within the scope of this paper, we focus first on organization, self-organization and emergence of the event, and then on spatial and temporal scales of the catastrophes. The organization is a key concept of complexity. In the catastrophe field, complexity of organization results essentially from the self-organization of the systems (the system develops its internal constitution and its behaviour because of the interactions between its various components and not because of an external strength). Phenomena as different as mantels of snow, seismic hazards, behaviours of the persons and the crowd have characteristics of selforganization allowing the emergence of new events: snow avalanches, earthquakes, collective panic. A particular attention will be given to the emer-
gence of collective panic in a context of catastrophe. We observe that emergent properties appear after the interactions between the individuals and the crowd happened It means that we need to take into account the multi-scales
aspect in order to be able to study the behaviours. The complex systems of catastrophe have characteristics able to emerge at higher or lower levels of scales. It allows us to study the complexity of the disasters through the scales. The disasters belong to the various temporal and space scales.