Directional analysis of community wildfire evacuation capabilities

Abstract

Wildfires are a natural part of forest ecosystems, but sometimes pose a threat to communities. In Canada, when public safety is threatened by a wildfire encroaching into the wildland-urban interface (WUI), fire management agencies will recommend that local authorities evacuate the area. If a fire spreads quickly towards a community and egress capacity is insufficient, public safety can be compromised. This paper presents an interdisciplinary approach for assessing community directional vulnerabilities for wildfire evacuation, combining techniques from wildland fire science and transportation engineering. For a selection of communities in Alberta that were assessed as being potentially vulnerable to wildfire, we explored the directional configuration of the transportation network in relation to a directional assessment of wildfire exposure. We first plotted the viable fire pathways and transportation facility characteristics, and then compared estimated fire encroachment times against estimated community egress times, directionally around each community to show evacuation vulnerabilities. Our results show that some communities, mainly within the Boreal Forest, Foothills and Rocky Mountain natural regions, have egress routes that are highly exposed to potential wildfire encroachment. Our findings also indicate that the evacuation timing for some larger communities needs attention, given relationships between estimated fire travel times and evacuation times. The results can be used to inform evacuation preparedness planning and proactive mitigation efforts.