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1.3: Hazards, Emergencies, Disasters, and Catastrophes

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    Hazards, emergencies, and disasters afflicted human societies much longer than either the profession of emergency management or academic disaster research has existed. Thus, many vernacular terms have arisen that refer to the negative consequences of environmental events—accident, emergency, crisis, disaster, catastrophe, tragedy, and calamity, to name a few. Over the years, many of these terms have become embedded in the American vocabulary, often introduced through the mass media or literary usage. As such events have become the focus of academic study and professional emergency management, it has also become necessary to devise technical—as opposed to vernacular—meanings for them to communicate a standardized meaning for each of these terms. For the purposes of this introduction to emergency management, it is important to distinguish the meaning of three terms: hazards, disasters, and emergencies.


    The environment humans occupy consists of natural and technological components, each of which contains elements that pose a variety of risks to the human occupants and their property. These risks include both health and safety dangers for the occupants themselves and dangers to the physical or material culture created by the occupants. The risks arise from the intrusion of the human use system into natural and technological processes. The term hazard captures the notion that, to the extent that people co-exist with powerful natural and man-made processes, there is a non-zero probability that the natural variation in these processes will produce extreme events having very negative consequences (Burton, Kates & White, 1993; Cutter, 2001). The human danger posed by these hazards varies with the level of human intrusion and the knowledge and technology associated with the hazard (Lindell & Perry, 1992). Tsunami (seismic sea waves) hazard is nonexistent in Ames, Iowa, because human occupancy at that location is so far from the runup zones near the ocean shore, but tsunami hazard is very significant along the Pacific coast—especially the Hawaiian islands. Hazards are inherently probabilistic; they represent the potential for extreme environmental events to occur. Thus, hurricane hazard refers to the potential for hurricanes to affect a given location. Hurricane hazard does not describe the condition when a hurricane strikes a coastal community causing death, injury, and property destruction. Of course, to achieve long-term survival, humans must adjust to or accommodate both natural and man-made processes in some fashion. The classic definition of hazard adjustment focuses upon the modification of human behavior (broadly speaking, to include even settlement patterns) or the modification of environmental features to enable people to live in a given place (or with a given technology) under prevailing conditions (Lindell & Perry, 2004).


    The term emergency is commonly used in two slightly different but closely related ways. The first usage of the term refers to an event involving a minor consequences for a community—perhaps a few casualties and a limited amount of property damage. In this sense, emergencies are events that are frequently experienced, relatively well understood, and can be managed successfully with local resources—sometimes with the resources of a single local government agency. Emergencies are the common occurrences we see uniformed responders managing—car crashes, ruptured natural gas pipelines, house fires, traumatic injuries, and cardiac crises. They are managed via (usually government, but sometimes private) organizations with specially trained, specially equipped personnel. One commonly associates emergencies with fire departments, police departments, and emergency medical services (EMS) organizations. These events are “routine” in the sense that they are well understood and, thus, elicit standardized response protocols and specialized equipment (Quarantelli, 1987). Nonetheless, it is important to understand each emergency can present unique elements; experts caution there is no such thing as a “routine” house fire. The belief that each new fire will be like all the previous ones has a high probability of producing firefighter deaths and injuries (Brunacini, 2002).

    The second usage of the term emergencies refers to the imminence of an event rather than the severity of its consequences. In this context, an emergency is a situation in which there is a higher than normal probability of an extreme event occurring. For example, a September hurricane approaching a coastal community creates an emergency because the probability of casualties and damage is much greater than it was in March before hurricane season began. The urgency of the situation requires attention and, at some point, action to minimize the impacts if the hurricane should strike. Unlike the previous usage of the term emergency, the event has not occurred but the consequences are not likely to be minor and routine methods of response are unlikely to be effective if the event does occur.


    The term disaster is reserved for the actual occurrence of events that produce casualties and damage at a level exceeding a community’s ability to cope. As Table \( \ref(1) |) indicates, a disaster involves a very specific combination of event severity and time/probability. Unlike the uncertain time of impact associated with a hazard (whether or not the impact would exceed community resources), a disaster reflects the actuality of an event whose consequences exceed a community’s resources. Unlike imminent emergencies, the consequences have occurred; unlike routine emergencies having minor impacts, disasters involve severe consequences for the community. By extension, a catastrophe is an event that exceeds the resources of many local jurisdictions—in some cases crippling those jurisdictions’ emergency response capacity and disrupting the continuity of other local government operations. Hurricane Katrina’s destruction of the local emergency response agencies and disruption of other local government agencies in Louisiana, Mississippi, and Alabama certainly qualifies for this designation.

    Prince’s (1920) study of an explosion in Halifax, Nova Scotia was the first modern piece of disaster research, but it was twelve years later that Carr (1932) made the first attempt at a formal definition of disaster. Presently, disaster is commonly defined as a nonroutine event in time and space, producing human, property, or environmental damage, whose remediation requires the use of resources from outside the directly affected community. This definition captures the two features that are minimally (and traditionally) cited as features of disasters: they are out of the ordinary events whose consequences are substantial enough to require that extra-community resources be marshaled to respond to and recover from the impact (Quarantelli, 1984; Perry, 1991; Tierney, Lindell & Perry, 2001). There are many different definitions of disaster present in the professional and academic literature, but most of them include the dimensions listed in this definition. In addition, some of the other definitions specify the mechanism that generates the event such as acts of God, social injustice, acts of nature, aspects of social organization, etc. As will be discussed later in this chapter, there are important distinctions to be made among different types of disasters and the ways in which emergency management strategies vary with the source of the disaster (Drabek, 1997). Whether one believes God, nature, social injustice, or purposeful encroachment produce disasters certainly affects the attitude we express toward victims. The academic community, in particular, is still debating the details of such distinctions and consensus about the specific details of different meanings is still developing (Quarantelli, 1998). However, in the profession of emergency management, the focus is typically on the assumption that disasters are caused by the overlap of human use systems with natural and technological processes and the charge is to minimize the negative consequences. At least on this applied level, emergency managers can operate on a concise definition of disasters, while remaining cognizant that the concept can be extended in a variety of ways and has myriad dimensions.

    Table \( \PageIndex{1} \). Relationships Among Hazards, Emergencies, Disasters, and Catastrophes.





    Demand compared to

    community capacity

    Less than




    Greater than




    1.3: Hazards, Emergencies, Disasters, and Catastrophes is shared under a Public Domain license and was authored, remixed, and/or curated by LibreTexts.

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