Evacuation is a social process where agents relocate from one area threatened by exceptional social and structural disruption to an area perceived as less threatening. Five main concepts characterize evacuation. First, evacuation is a socially constructed process in that humans play a significant role in the development of social and physical structures that may facilitate or hinder the ability to evacuate. Second, evacuation is a process in that there exists a before, during, and after, as opposed to a singular event or moment in time. Thus, while it is common to think of evacuation as lasting for a specified duration, the concept is best understood through an exploration of the lead time before the threat, the presentation of the threat, and the aftermath following the ...