The prediction and management of "extreme events", from volcanic eruptions to floods to stock market crashes, requires a careful analysis of the hazard event, its inputs, and its consequences. Data of different kinds, and of differing fidelity, must be incorporated into a detailed analysis of the impending hazard. Strategies for minimizing the hazard impact must be decided, and a plan of action set in motion. In many natural hazard scenarios, precursory information becomes available before the disaster strikes. Responding to an impending hazard means that time is limited, so analysis and decision-making must proceed on an accelerated timetable. Modeling, numerical simulation, leading to predictive capacity, play an important role during this pre-event timeframe.