Scenario-Based Modeling of Community Evacuation Vulnerability

Kevin D. Henry, Tim G. Frazier


Evacuation models can be used to determine evacuation capacity, by estimating the time required for evacuating populations to leave areas exposed to a hazard. Disaster management practices and evacuation modeling are generally carried out to prepare for ‘worst-case’ conditions. However, hazard severity is highly variable. Performing evacuation modeling for multiple hazard scenarios may provide flexibility and a comprehensive understanding of evacuation capacity. A case study was undertaken to analyze the merit of scenario-based evacuation modeling. Results demonstrate a difference in clearance time between maximum and historic tsunami scenario modeling. During a smaller-scale event, allowing the maximum scenario population to evacuate can add congestion and inhibit evacuation of at-risk populations. Managing evacuation can improve evacuation efficiency by preventing unneeded congestion. Results show that traditional worst-case-scenario modeling may lead to overestimation of time needed to evacuate. Planning under such a scenario may increase risk to smaller-scale hazards.

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