In December 2007, dry lightning ignited numerous bush fires on Kangaroo Island. Four of the fires continued to burn for two weeks, consuming over 20% of the islands' vegetation. The unique environment of Kangaroo Island is strongly influenced by the surrounding cold ocean waters, and the local meteorology, topography and vegetation were factors that influenced the evolution of the bushfires. This case study investigates the fire weather and fire behaviour by examination of meteorological observations, archived high-resolution numerical weather prediction models and documented and anecdotal observations of fire behaviour. The discussion covers three main findings. The first is how atmospheric instability enhanced activity of one fire in a convergent sea breeze regime. The operational index currently used for forecasting instability did not account for the low level process; however FireCAPE indicated potential for development of a convection column. The second finding centres on how local internal boundary layer processes impacted spatial and temporal variation in fire weather parameters on a day of near-severe fire danger. The performance of high-resolution numerical weather prediction models in capturing local processes on this day is assessed and subsequent implications for using atmospheric model output as input for fire behaviour simulations are then discussed. The third finding focuses on a fire regime where local fuel and topography, as well as feedback between the fire and atmosphere were seen to impact fire behaviour. However, as the emphasis of fire weather forecasting and fire management in Australia is on the McArthur ratings, not all environmental elements would typically be considered in anticipating the fire’s evolution. This study will describe processes that occurred which are not explicitly captured in current fire prediction procedures. It will also consider how the discrepancies may be critical to firefighter safety and to prescribed burn outcomes.
Collection(s) and Series: CAWCR technical report- No. 53
Format: Digital (Free), Hard copy