The following definition was used in FORTRESS FP7, and published by Pescaroli and Alexander (2015) as peer-reviewed in Planet@Risk, the journal of the Global Risk Forum Davos. Cascading disasters have to be intended as a self-standing cathegory of events, distinguished by the non-linear escalation of secondary emergencies (Figure 1).
"Cascading disasters are extreme events, in which cascading effects increase in progression over time and generate unexpected secondary events of strong impact. These tend to be at least as serious as the original event, and to contribute significantly to the overall duration of the disaster's effects. These subsequent and unanticipated crises can be exacerbated by the failure of physical structures, and the social functions that depend on them, including critical facilities, or by the inadequacy of disaster mitigation strategies, such as evacuation procedures, land use planning and emergency management strategies. Cascading disasters tend to highlight unresolved vulnerabilities in human society. In cascading disasters one or more secondary events can be identified and distinguished from the original source of disaster." 
Figure 1 - (a) Linear path of events in disasters, and (b) non-linear path of cascading, including amplification and subsidiary disasters (Pescaroli and Alexander 2015).
- ↑ www.fortress-project.eu
- ↑ [Pescaroli G. and Alexander D.E. (2015). A definition of cascading disaster and cascading effects: Going beyond the “toppling dominos” Planet@Risk, 2(3), 1-4 ]