Behaviour of a Very Fast Grassland Wildfire on the Riverine Plain of Southeastern Australia.

Abstract

A grassland wildfire burnt 120,000 ha in the western Riverina of New South Wales and caused exten sive losses of sheep and fencing. The rate of spread of the fire was accurately recorded at 6.4 m s-1 (23 km h-1) as it traversed one property and on the basis of conservative estimates of fuel loads measured later on unburnt patches, a fireline intensity was calculated at around 20,000 kW m-1. This rate of spread is one of the highest recorded for grassland wildfires in southern Australia and represents an important datum point for wildfire behaviour models. Quite reasonable predictions of rate of spread were pro vided by the McArthur Mark 4 fire danger model, how ever, the Mark 5 model seriously underestimated rate of spread for this and two other grassland wildfires.