Spatiotemporal changes in conterminous US wildfire exposure from 1940 to 2010

Abstract

This study utilizes fine-scale, built-environment data in conjunction with past wildfire events to assess historical spatiotemporal changes in wildfire likelihood and societal exposure to wildfires for the conterminous USA. Results indicate that conterminous US wildfire exposure has increased substantially over the past 70 years due to escalating wildfire likelihood and an expanding human-developed footprint. Although wildfire exposure has increased as a whole throughout the conterminous USA, the relative contributions of wildfire likelihood and the built environment to exposure vary from region to region. Wildfire likelihood plays a larger role in exposure in the western USA due to a greater frequency of large wildfires. Conversely, built-environment density has a stronger influence on exposure than wildfire likelihood within the eastern and central USA. In all, the total number of homes and total developed land area prone to wildfire impacts has increased by nearly 1350% since 1940 throughout the conterminous USA. Findings presented in this study highlight the importance of considering both hazard likelihood and built-environment magnitude when assessing wildfire exposure. Given the rapid historical amplifications of both wildfire likelihood and societal exposure, communities in wildfire-prone areas should implement and/or continually evolve their existing wildfire prevention strategies to include the effects of expanding development to reduce future damages and losses. The continual enactment and adaptation of wildfire suppression and mitigation strategies will ultimately result in more disaster-resilient communities as climate and society continue to influence the future US wildfire exposure.