Background

Estimating the factors affecting the probability of a wildfire reaching the wildland urban interface (WUI) can help managers make decisions to prevent WUI property loss. This study compiles data on fire progression, wind, landscape characteristics, and fireline built to estimate the probability of an active fire reaching nearby WUI blocks. We started by constructing funnel-shaped analysis zones between recorded fire perimeters and WUI blocks. We used zonal analysis to characterize landscape and fireline arrangement and then used a random forest modeling approach to quantify the probability of fire reaching the WUI blocks.

Results

We found the probability of WUI exposure from an active fire had close relationships with several explanatory variables including wind gust velocity, suppression difficulty, control potential, fireline arrangement, road densities, WUI block sizes, and the distance between WUI and the fire’s front. We found that the most important predictor variables influencing WUI exposure probability were gust, fireline arrangement, and distance from a fire ignition location to a WUI. We found that random forest models can achieve reasonable accuracy in estimating WUI fire exposure probabilities.

Conclusions

Focal analyses and random forest models can be used to estimate WUI fire exposure probabilities in support of large fire suppression decisions at division to incident scales.