As previously noted, 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. Proximity to, and location within, grassland are also factors. Therefore a distance based, two-point scale is applied to addresses in grassfire prone areas:
- Within (2) – distances less than 20 m from extensive grassland
- Outside (1) – distance greater than 20 m from extensive grassland
Note: Existence of corridors of grassland between extensive areas
of grassland may aggravate risk beyond the risk rating provided despite the distance
between the building and the grassland. On the other hand, specific site factors or
owner preparedness may mitigate this risk.