<p>Traditional wildfire spread prediction models often struggle to simulate fire propagation accurately in complex terrain or under strong wind conditions due to their semi-empirical nature and simplified treatment of fire-atmosphere interactions. This study presents a novel rapid fire spread model that integrates Briggs’ buoyant plume theory, the Rothermel fire spread model, and Huygens’ principle of wave propagation. The model is designed to simulate fire behavior in grasslands with complex terrain, enabling detailed representation of fire front dynamics. By analytically solving flame plume equations, the model quantifies the combustion heat production and its impact on surrounding wind fields through buoyant lifting effects. This innovative two-way coupling of atmosphere-fire interactions enhances the model’s ability to simulate fire behavior under various environmental conditions. The model incorporates multiple factors, such as the wind speed, terrain, flame plume entrainment, fuel moisture content, packing ratio, and effective flame width, overcoming the limitations of traditional models in accurately capturing the shape of fire fronts. Validation through numerical simulations demonstrates that the model effectively reproduces both the temporal and spatial evolution of fire fronts across different wind and terrain conditions. In benchmark tests with a 100-meter ignition line, the model shows remarkable agreement with fully-coupled dynamic simulations, with a mere −10.38% deviation in fire spread rate while accurately replicating fire front patterns. The proposed model offers high computational efficiency and can serve as a valuable tool for wildfire risk assessment and emergency response.</p>