The focus of this chapter is on the role of GIS in managing sudden impact disasters like floods and fires, rather than on slow onset hazards like radon, water pollution, land erosion, or other natural or technological hazards that occur gradually over time. The chapter purpose is twofold: first to review a number of example applications of GIS in emergencies; and, second, to demonstrate an example application of GIS in regional evacuation analysis, namely evacuation vulnerability mapping. In this way, the chapter can be viewed as a synoptic discussion of GIS in emergency management followed by a demonstration of one particular application.