SnowBall is a €5M STREP R&D proposal of 36 months. Its overall objective is to increase preparedness and response capacities of decision-makers, emergency planners and first responders in respect to amplifying hazards in large disasters.SnowBall consists in a deep analysis of cascading effects and development of methods to anticipate them; and in a Decision Support System able to display current crisis monitoring and results of simulated decisions integrating cascading effects, thanks to a data collection system, an Events Log Database, Simulators and a Dashboard. SnowBall innovates in its modular approach to crises, its modelling techniques, its agent-supported coupled grid simulations, its generic Events Log Database and tools to follow public behaviour (Emergency Alert, social networks, mobile application).SnowBall encompasses 8 work packages: 1- Management; 2- Technical supervision; 3- Cascading effects methodology; 4- Event log database; 5- Simulation tool; 6- Crisis Management dashboard; 7– Experimentation; 8- Dissemination and Exploitation.SnowBall comprises 11 partners from 8 countries covering the full competence scope required: 2 industrials (Gedicom - Emergency Alert System; Cofely INEO - Events log database), 2 Research Institutes and 3 Universities focussed on different segments of risks assessment: LUPT-PLINIVS (natural hazards); Fraunhofer EMI (critical infrastructure socio-technical simulation); EMAUG (human behaviour); UCL (public health) and ISMB (cloud, data process, mobile services), 3 end-users (Polish Fire School; Ministry of Interior of Finland represented by ESC; and Hungarian Red Cross) and 1 consultancy (EP).The main expected impacts of SnowBall are a substantial scientific contribution, a fosterer of capacity to face complex crisis situations by better predicting cascading effects and integrating population behaviour in simulations, a contribution to the security of EU citizens; and a commercially viable project contributing to EU competitiveness.