The paramount goal of disaster management activities is to reduce, as much as possible, the degree to which a community’s condition is worsened by a disaster relative to its pre-disaster condition. There are many actions undertaken by participants in disaster management that support this goal both pre-disaster (to forestall or reduce potential damage) and post-disaster (to recover from actual damage), and ideally these activities would reduce the potential effects of a disaster to the point of elimination. Yet the very nature of disasters makes this ideal unachievable. There are five major characteristics of disasters that make them hard to overcome (for a more detailed explanation, see Donahue and Joyce, 2001; Waugh, 2000):
Disasters are large, rapid-onset incidents relative to the size and resources of an affected jurisdiction. That is, they harm a high percentage of the jurisdiction’s property or population, and damage occurs quickly relative to the jurisdiction’s ability to avert or avoid it. They may also directly impact the resources and personnel available to respond. As a result, response to disasters evokes a profound sense of urgency, and coping with them drains a jurisdiction’s human resources, equipment, supplies, and funds. If pre-incident data are available, geospatial analysis can provide important insight into the nature and extent of changes wrought by disasters.
Disasters are uncertain with respect to both their occurrences and their outcomes. This uncertainty arises because hazards that present a threat of disaster are hard to identify, the causal relationship between hazards and disaster events is poorly understood, and risks are hard to measure—that is, it is difficult to specify what kind of damage is possible, how much damage is possible, and how likely it is that a given type and severity of damage will occur. Geospatial models can help predict the locations, footprints, times, and durations of events, and the damage they may cause, so that jurisdictions can better prepare for them.
Risks and benefits are difficult to assess and compare. Disasters present emergency planners, emergency managers, and policy makers with countervailing pressures. On the one hand, it is important to minimize the exposure of populations and infrastructure to hazards; on the other, people want to build and live in scenic, but hazard-prone, areas and often oppose government regulation. Further, how should the various levels of government address the balance between providing relief to the victims of disasters and the need or desire to avoid encouraging risk-accepting behavior; also, to what extent should the costs of such behavior be shifted from those who engage in this behavior to the larger population? While