Spatial Distribution of Wildfire Threat in the Far North: Exposure Assessment in Boreal Communities

Abstract Increased wildfire activity has raised concerns among communities about how to assess and prepare for this threat. We modified an existing approach to assess decadal wildfire hazards based primarily on ember dispersal and wildfire proximity, referencing landscape changes from 1984 through 2014. The original method created multiple maps to capture ember dispersal and spread at different scales. Instead, we integrated this multi-scale information into a single exposure layer and utilized a straightforward flammability hazard classification scheme. Binomial exact and Kruskal–Wallis tested the relationship between exposure values, underlying flammability hazard classes, and wildfire scars, respectively, in three arctic communities (Anchorage and Fairbanks, Alaska and Whitehorse, Yukon) with a range of wildfire histories and amounts of urbanization. There was a significant difference in exposure values among burned and unburned locations (p < 0.001) and flammability hazard classes (p < 0.001). Areas with high exposure values are more prone to burn and thus desirable for mitigation actions. Wildfire fire hazards are extremely high within Whitehorse and Fairbanks, and lower in Anchorage. By working with wildfire practitioners, communities, and residents, we have created a tool that can rapidly assess wildfire hazards and be easily modified to help identify and prioritize areas for mitigation activities.