Wildfire Towers Drive Firebrand Lofting: Insights from Coupled Fire-Atmosphere Model Simulations

Abstract Previous studies have highlighted the complexity of wildfire behavior, emphasizing the significance of firebrand dynamics in contributing to the spread and severity of wildfires. While these studies provide foundational knowledge, the specific role of wildland fires' towers and troughs in firebrand lofting has never been addressed. This work aims to illustrate the intricate relationship between the wildland fire tower and trough phenomena and firebrand lofting. Through physics-based simulations, we show the presence of wildland fire towers and troughs drives the spatial distribution of generated firebrands as well as the vertical trajectory of lofted firebrands. We found that the majority of firebrands (78.85 %) get lofted from wildfire towers which are the regions of updrafts while the remaining firebrands enter into troughs during the lofting process which severally limits the height and distance that they travel. The results of this study are helpful for foresters and land managers in planning as well for researchers in advancing the existing model capabilities that can save communities and enhance the safety of firefighters from wind-driven fires where there are higher risk of spot fires.