Disasters have massive human and economic costs. They may cause many deaths, severe injuries, and food shortages. Most incidents of severe injuries and deaths occur during the time of impact, whereas disease outbreaks and food shortages often arise much later, depending on the nature and duration of the disaster.
Anticipating the potential consequences of disasters can help determine the actions that need to be started before the disaster strikes to minimize its effects.

World Health Organization (WHO) defines a disaster as “a sudden ecological phenomenon of sufficient magnitude to require external assistance”. It is also defined as any event, typically occurring suddenly, that causes damage, ecological disruption, loss of human life, deterioration of health and health services, and which exceeds the capacity of the affected community on a scale sufficient to require outside assistance (Landsman, 2001). It is an emergency of such deaths, injuries, illness, and property damage cannot be effectively managed with routine procedures or resources.
Disaster is further defined as an event in which a society or a community undergoes acute deprivation of food and other basic necessities due to natural and man made calamities to such an extent that the normal function of the society or the community is disrupted and that it cannot subsist without outside intervention