Fire response to natural wind versus constant wind

Abstract

While the relation between wildland fire spread rate and wind has been a topic of study for over a century, very few previous studies report measurements of fire rate of spread in controlled winds exceeding 5 m/s. In this study measurements of fire rate of spread, flame residence time, and energy release are reported for fires burning under controlled atmospheric conditions in a shallow bed of pine needles subject to winds ranging from 0 to 27.2 m/s (6 m agl). The data suggest that when winds are less than 5 m/s fire rate of spread increases linearly with wind speed. As wind speed exceeds 5 m/s the fire rate of spread response increases at a rate approximately 5 times greater. When fires are burned in winds replicating natural spatiotemporal variability in speed and direction the rate of spread is 20 to 90 % greater than when burned under constant steady winds.