Home > Academics > Disaster courses > Definition of disaster

According to the World Health Organization, a disaster can be defined as a sudden ecologic phenomenon of sufficient magnitude to require external assistance.

From the emergency department perspective, a disaster exists when the number of patients presenting in a given space of time are such that the emergency department cannot offer even minimal care for them without external assistance.

Disasters that are characterized by the production of large number of deaths and injuries are also referred to as "mass casualty incidents."