Analysis by Risk Frontiers of major historical bushfires shows distance from the bushland fringe to be the single most important factor determining the probability of building destruction given an extreme fire in adjacent bushlands. A distance-based, five-point scale is applied to addresses in bushfire-prone areas:
- Very High (5) – distances less than 100 m from extensive bushland
- High (4) – distance between 100 – 200 m from extensive bushland
- Medium (3) – distance between 200 – 400 m from extensive bushland
- Medium-Low (2) – distance between 400 and 700 m from extensive bushland
- Low (1) – distance between 700 and 1000m from extensive bushland
- Negligible (0) – distance greater than 1000m from extensive bushland
Areas with a high potential for bushfire are largely confined to the southeast and southwest of the continent and Tasmania. Areas north of the Tropic of Capricorn do experience bush or grassfires but to date have not involved significant property losses.
Site elevation and aspect can influence bushfire risk and these are also included in the database.