Citation

Moon K, Duff TJ, Tolhurst KG. Fire Safety J. 2019; 105: 320-329.

Copyright

(Copyright © 2019, Elsevier Publishing)

DOI

10.1016/j.firesaf.2016.02.005

PMID

unavailable

Abstract

Operational forest fire simulation models typically incorporate reduction factors to modify winds forecast to meteorological standards for open environments so that they characterise the sub-canopy winds that drive fire spread. While these reduction factors may vary between forest types, they are typically static; wind reduction is constant regardless of height within the sub-canopy space and forecast wind speed. The validity of using static wind reduction factors was investigated by measuring sub-canopy horizontal wind speeds at different heights in seven vegetation types across Victoria, Australia. We found that the vertical wind profiles were highly variable, with substantial variation in response to height above ground and the prevailing (open environment) wind speed. The combined effect of these influences meant that within each forest type, wind reductions can vary by factors of greater than four. As wind is proportional to fire spread in most simulation models, this high level of variation will be carried through to wildfire predictions and may have consequences for decision making. We believe further investigation into the use of wind reduction factors is warranted, in particular the potential to recognise dynamic wind profiles.

Language: en

Keywords

Bushfire; Fire models; Sub-canopy wind; Vegetation structure; Wind sampling