Destination unknown: Examining wildfire evacuee trips using GPS data

Effective wildfire evacuation planning requires understanding where evacuees are likely to travel and temporarily reside. Detailed information on evacuee destinations is a valuable input into critical decisions related to evacuation traffic control, shelter assignment, and return-entry planning. To improve our understanding of where evacuees stay, we analyzed GPS data generated by mobile devices from the 2019 Kincade Fire evacuation in Sonoma County, California. A new algorithm was developed to infer evacuee stops and destinations from mobile device GPS data. Evacuees were placed into distinct subgroups associated with their warning and departure context (e.g., self-evacuee, warned evacuee, ordered evacuee, shadow evacuee). The results reveal a surprising diversity of destinations not captured and mapped in prior studies. Analysis of the sub-groups showed marked differences in destination types and travel distances. The results of this study can aid in planning for future wildfires by providing emergency managers with detailed findings on empirical evacuee destination distributions.