Assessing Risk and Prioritizing Safety Interventions in Human Settlements Affected by Large Wildfires

The large wildfires of June 2017 disturbed many communities in central Portugal. The civil parish of Alvares was severely affected, with about 60% of its area burnt. Assessing the risk of large wildfires affecting local communities is becoming increasingly important, to reduce potential losses in the future. In this study, we assessed wildfire risk for the 36 villages of Alvares parish, by combining hazard, exposure and vulnerability analysis at the settlement scale. Hazard was obtained from fire spread simulations, which integrated exposure together with population and building density within each village. Vulnerability was based on the sociodemographic characteristics of the population, ranked with a hierarchical cluster analysis. Coping capacity was also integrated, considering the distance of each village to the fire station and the time needed for residents to reach a shelter. We simulated 12 different land management scenarios, regarding the implementation of a fuel-break network and the level of forest management activities. The potential effects of each scenario in the exposure and risk levels of the settlements were evaluated. The results show that, for a business-as-usual scenario, 36% of the villages are at high or very high risk of wildfires. Examining each risk component, 28% of the villages are highly exposed, 44% are highly vulnerable, and 22% do not have a potential shelter on-site, calling for different intervention strategies in each specific risk dimension. All the land management scenarios, even if designed for other purposes than the protection of settlements, could decrease the proportion of highly exposed villages at different levels, up to a maximum of 61%. These findings can contribute to adjust prevention and mitigation strategies to the risk levels and the characteristics of the population and the territory, and to prioritize the protection and emergency actions at the local scale.