Parcel-Level Risk Affects Wildfire Outcomes: Insights from Pre-Fire Rapid Assessment Data for Homes Destroyed in 2020 East Troublesome Fire

Parcel-level risk (PLR) describes how wildfire risk varies from home to home based on characteristics that relate to likely fire behavior, the susceptibility of homes to fire, and the ability of firefighters to safely access properties. Here, we describe the WiRe Rapid Assessment (RA), a parcel-level rapid wildfire risk assessment tool designed to evaluate PLR with a small set of measures for all homes in a community. We investigate the relationship between 2019 WiRe RA data collected in the Columbine Lake community in Grand County, Colorado, and whether assessed homes were destroyed in the 2020 East Troublesome Fire. We find that the overall parcel-level risk scores, as well as many individual attributes, relate to the chance that a home was destroyed. We also find strong evidence of risk spillovers across neighboring properties. The results demonstrate that even coarsely measured RA data capture meaningful differences in wildfire risk across a community. The findings also demonstrate the importance of accounting for multiple aspects of PLR, including both hazards and susceptibility, when assessing the risk of wildfire to homes and communities. Finally, the results underscore that relatively small actions by residents before a fire can influence wildfire outcomes.

Automated summary

Parcel-level risk (PLR) is the variation of wildfire risk from home to home based on characteristics related to fire behavior, home susceptibility to fire, and firefighters’ access. The WiRe Rapid Assessment (RA) is a tool designed to evaluate PLR by using a small set of measures for all homes in a community. This study investigates the relationship between 2019 WiRe RA data and the destruction of assessed homes in the 2020 East Troublesome Fire. The results show that overall parcel-level risk scores and individual attributes are related to the chance of home destruction. There is also evidence of risk spillovers across neighboring properties. The findings highlight the meaningful differences in wildfire risk captured by even coarsely measured RA data and emphasize the importance of considering multiple aspects of PLR when assessing wildfire risk. Lastly, the results underscore the influence of relatively small actions by residents before a fire on wildfire outcomes.