Infrasound generation by large fires: experimental results and a review of an analytical model predicting dominant frequencies

Recent fires in the vicinity of an infrasonic observatory near Boulder, Colorado demonstrated that intense combustion processes radiate significant infrasound. A fire 1.3 kilometers from the observatory was recorded for about 6 hours, and the pressures detected increased and waned in concert with the reported intensity of the fire. This event is unique in that the source region acoustic signatures are defined with minimum propagation effects and no terrain blockage. This fire and several others provided data for comparisons with an analytical model predicting the dominant frequencies produced. We discuss the implications of these results.