The behavior of wildland fires and the dispersion of smoke from fires depends, in part, on ambient and fire-induced winds that work to spread fires across the landscape and mix fire emissions into the atmosphere. These winds are typically not steady, but rather highly variable or turbulent with substantial wind gusts. Northern Research Station scientists have built upon previously reported wildland fire turbulence research to discover new properties of the atmospheric turbulence regimes that can develop in the vicinity of wildland fires occurring in forested environments.
Using observational atmospheric data collected in the vicinity of advancing fire fronts during wildland (prescribed) fire events in forest stands, scientists examined the combined effects of forest canopies and heating in the lower atmosphere due to fires on the production of turbulence energy (wind-gust magnitudes), the skewness of turbulent velocity distributions (wind-gust variability), and the directional partitioning of turbulence energy (horizontal vs. vertical wind gusts). The study results suggest that wind-gust characteristics in the vicinity of wildland fires in forested environments can vary substantially from pre- to post-fire-front-passage periods and are height dependent within forest canopies. These new insights into wind gust behavior provide the foundation for improving fire behavior and smoke dispersion prediction systems.