Linking Heterogeneity at the Wildland Urban Interface to Wildfire Dynamics

The complex interactions between atmospheric and fire-induced winds are a persistent obstacle to accurately predicting wildfire front behavior. There are a multitude of wildfire spread models, with one primary distinction being the level of fire-atmosphere coupling in each. Coupling of fire-induced winds and ambient winds in numerical models is carried out through linking the heat and mass fluxes from the wildfire with the surface energy fluxes in the atmospheric model. The challenge in this coupling is increased with the introduction of heterogenous surface conditions, e.g., terrain, canopies, buildings. To better understand the dynamic coupling of fire-induced winds and atmospheric winds at microscales, the fast-response wildfire model QES-Fire was used to study the effects of fire-induced winds near structures, and the relative importance of the momentum deficits caused by canopies and structures on fire-induced winds.