The role of released moisture in the atmospheric dynamics associated with wildland fires

Abstract

Combustion of woody material produces and releases water, but the effects of this water on the atmospheric circulation created by a wildfire are rarely recognized, let alone understood. This paper presents observational data and basic physical arguments to support the hypothesis that this moisture can constitute a large portion of the total water content in a fire plume. Calculations demonstrate the effects this moisture could have on fire-driven atmospheric circulations, specifically updrafts and downdrafts, on time and space scales important for fire behavior and fire-fighter safety. This study should be considered exploratory; it does not prove the presence or importance of this moisture, but seeks to show that further study is needed to determine how much moisture a fire adds to the air, and whether that amount is or is not important.