PEDESTRIAN WALK TIME MAPS FOR TSUNAMI EVACUATION IN THE ABERDEEN AREA WASHINGTON

Tsunami evacuation walk time maps show estimated walk times for evacuating tsunami hazard areas. They are created from models that use the Pedestrian Evacuation Analyst Toolkit (PEAT) developed by the U.S. Geological Survey to aid in evacuation planning for natural hazards. PEAT uses elevation changes and type of land cover to calculate walking speed along an evacuation route. Areas with steep terrain, heavy vegetation, or obstructions will take longer to evacuate. There are limitations to PEAT as it cannot predict the secondary impacts from disasters such as damage to buildings or infrastructure, fallen power lines or trees, ruptured underground utilities, and settling or shifting of the ground surface. These unpredictable effects may slow evacuation time. To mitigate these issues, we assume a slow walk pace (2.5 mph), taken as a conservative estimate for most persons. Individuals with mobility restrictions should consider additional measures to ensure that they have assistance or other means of evacuating from the inundation area.

Emergency managers, planners, and local decision makers use these maps to plan evacuation routes, critical resources, and response. The successful completion and use of these maps is vastly improved by involving these professionals in the process. They provide local knowledge that otherwise would not be known or included in the map.

The PEAT results are brought into ArcGIS Pro and Adobe Illustrator where we apply cartographic standards to produce a visually appealing, detailed view of the time it would take to evacuate on foot from the tsunami inundation zone. To maximize safety, the public is encouraged to use these maps before the next tsunami occurs. Studying routes ahead of time, practicing walking them, identifying any issues along the way, and better understanding one’s personal walking pace is instrumental in emergency response.

The walk time maps also show how long it would take for the first tsunami wave to arrive, and where issues that impact evacuation might arise (such as destroyed bridges or isolated areas without evacuation paths). We have successfully created seven walk time maps to date working with local communities in each.