FORTRESS (Foresight Tools for Responding to cascading effects in a crisis) is a three year project that started in April 2014 and will end in March 2017. The aim of the project is to identify and understand cascading effects of a crisis by using evidence-based information from a range of previous crisis situations. Cascading effects in crisis situations are frequently caused by the interrelatedness and interdependency of systems and infrastructure; crises not simply affect one system or a part thereof, but cause a chain of effects. These effects spread disruptions in complex ways that makes them difficult to comprehend and deal with. A well-known example of such cascading effects is the meltdown of Fukushima’s nuclear reactors, after the power plant was hit by a tsunami, which in turn was triggered by an earthquake. FORTRESS aims to improve crisis management practices by identifying the diversity of such cascading effects. Its main outputs include the development of a predictive model addressing potential impacts of decisions made in crisis situations, and the development of an incident evolution tool to assist decision-makers in preparing and training for crises with cascading effects. FORTRESS is funded by the European Commission, and has thirteen partners from eight European countries.