Fire spotting effects in wildland fire propagation

Abstract

Wildland fire propagation is affected by events with random character. Two of them are turbulence, due to the Atmospheric Boundary Layer and to the fire-induced flow, and fire spotting, when sparks or embers are carried by convection and they start new fires when they land. Fire front position gets therefore a random character, too. A formulation which includes random effects due to both turbulence and fire spotting is discussed. It generalizes the level-set method for tracking random fronts. Under the assumption that fire spotting is a downwind-phenomenon, differences between fire propagation in the windward and in the leeward sectors are analyzed. In particular it emerges that the variability in time of the average ember jump-length and of the mean wind direction push fire advancement.