This document is the third in a series of special topics for consideration, as part of the Words into Action Guidelines on National Disaster Risk Assessment published by UNISDR. This section focuses on the assessment of cascading risks to create scenarios, tools and information that could join the triggers with their patterns of consequences and thus help visualize the potential structure of secondary emergencies.
A causal chain generates secondary disasters from the interaction between anthropogenic and ecological systems. Despite major efforts by the international community, many challenges are still present in efforts to mitigate such phenomena. For example, current risk management strategies are insufficient for estimating the probability of rare events and coincidences, and for understanding cascades and event trees. To improve the operational management of complexity, a system-wide approach to resilience is needed that embraces new forms of analysis, new methods and new tools. Cascading disasters and risks present substantial challenges both to citizens and to the emergency management community.