Improved Formula for the Drought Factor in McArthur's Forest Fire Danger Meter

Abstract

Summary McArthur's Forest Fire Danger Meter (Mark 5) is a key tool for assessing broadscale fire danger throughout eastern Australia. The Drought Factor, an indicator of the fuel availability as calculated by the meter, is a key input in calculating the Forest Fire Danger Index. The currently accepted analytic method for calculating the Drought Factor is reviewed and shown to give significantly different results to that calculated by McArthur's meter. This paper proposes a new formula for calculating the Drought Factor and shows that it fits McArthur's meter to a far better degree than the previously published formula.