Winds play a critical role in fire spread, but a fire itself can modify local winds, helping it grow even more quickly. Now NCAR and university scientists have created one of the first computer models to trace the interplay over time between fire behavior and winds, pointing the way toward future models that might aid in fire prediction and management. First results from this model were published in the May 1996 issue of the Journal of Applied Meteorology . Output from the fire-atmosphere coupled model shows the development of two fingers along a fire line. The line is just under two kilometers long, with the fingers developing at top and bottom.
Arrows depict horizontal winds.
Although forests vary in how they burn, the authors expect that their main findings will translate to a variety of settings. Most previous studies on fire and wind have assumed a straightforward relationship between large-scale winds and fire behavior. Air temperatures near a fire are lower than one might think. In the first several minutes of a new fire, the model shows surface temperatures soaring, which creates a chimney-like plume of rising air. In the model, the updraft strengthens and pulls in surrounding cooler air as a fire's heat output increases.