The phrase “spreads like wildfire” is well known but until recent discoveries through experiments conducted by scientists from the Missoula Fire Sciences Laboratory, University of Maryland and the University of Kentucky, we did not know well how wildfires actually spread. Specifically, it was unclear how radiation and convection heat transfer processes, which both occur in wildfires, are organized to produce wildfire spread. Now, evidence presented in a new study by FFS Research Forester and lead Mark Finney, Research Physical Scientist Jack Cohen, Mechanical Engineer Jason Forthofer, and Research Mechanical Engineer Sara McAllister, and six scientists Missoula, reveals how flame dynamics that produce and transport convective heat effectively governs the spread of wildfire.
Published July 2015 in the Proceedings of the National Academy of Sciences (PNAS), the Role of Buoyant Flame Dynamics in Wildfire Spread study led to the discovery of previously unrecognized flame behaviors and ways those behaviors cause wildfires to spread. Flame vorticity (circulations) and instabilities due to the buoyancy of flame gasses, cause wildfires to spread by forcing flames downward into the fuel bed and bursting forward ahead of the fire into fresh fuel (grass, brush, etc.), revealing that flame dynamics, not radiation heat as once believed, effectively governs wildfire spread. The information obtained through this research is significant with the potential to:
- Improve firefighter safety by providing better training to recognize and anticipate wildfire behavior
- Simplify the physical principles of wildfire spread that can lead to the development of improved prediction models, and
- Improve the ability to mitigate fuel hazards by accurately modeling and describing fuel contribution to wildfires.