Initial analysis of fire weather characteristics between south-east Australia and south-west of Western Australia

Abstract

Australia is a continent in which bushfires are an endemic part of the landscape. A bushfire can occur anywhere at some time of the year, restricted by the presence of flammable fuel, conducive weather conditions and an ignition source. Due to its size, Australia spans a wide range of geological and climatological zones, resulting in a large number of unique landscapes, from arid desert to rainforest to alpine, the genesis of a number of significant differences in fire weather between the east coast and west coast of the continent. The potential for disastrous fire is dictated by three factors that influence fire behaviour: (a) the type of vegetation (fuel) in which the fire is burning; (b) the weather; and (c) the topography in which the fire burns. This paper centers on (b) the weather, particularly the fire danger weathers measured by the McArthur Forest Fire Danger Index (FFDI). It concentrates on the comparison of fire danger weather conditions of south-east of Australia and south-west of Western Australia. Weather datasets since 1990 from almost all Automatic Weather Stations in Australia were acquired and 28 were selected and analysed. Furthermore, six sites were particularly chosen, one for each state/territory, for this comparison study. A number of fire danger severity measures were developed including the number of Extreme FFDI days per fire season and the longest number of consecutive Extreme FFDI days. The paper has a number of findings including the similarities of fire weather conditions of the two regions and their differences. This initial analysis motivates us to engage further research on other important fire risk factors such as vegetation, distribution of infrastructure, properties and population at risk, and possible correlation between the past fire ignitions including disastrous fire events and FFDI.