A system and method for tracking the growth of large-area wildland fires. The technique includes monitoring wind conditions in and around a wildfire using near-surface-sited sensors deployed by a high-altitude long-endurance (HALE) unmanned aerial vehicle (UAV), such as the Global Hawk. The deployed sensors measure a localized wind vector at multiple locations within and surrounding the wildfire, and transmit the wind data back to the UAV for relaying to a command center operated by fire management authorities, where the wind data are used to assist decision-making, including as input into wildfire growth prediction models. The sensors may provide additional data such as local altitude/elevation, pressure, temperature and relative humidity. The UAV may also carry sensors that provide additional data to be used by the fire management authorities or the wildfire growth prediction models—such as infrared images defining actively flaming areas, and visual images which indicate vegetation type and density.