Central Australian fires, 1974-75

In the northern half of Australia, fires are frequent in the dry season (winter and spring). Fire is often used as a land management technique, typically to burn off dry grass from the previous wet season, and to encourage regrowth of more nutritious feed in the following wet season. But lightning is also a major cause of wildfires in this area.

These fires are capable of spreading over vast areas of the arid and semi-arid inland, but are seldom serious in terms of life or property losses, because of the normal sparseness of the vegetation. This was not the case in 1974, however, when exceptional rainfall over most of the inland during the preceding summer wet season produced abundant grass and scrub growth. More rain in the winter and early spring of 1974 maintained this growth. However the return of dry conditions over the inland in the late spring (earlier in northern areas) allowed this abundant vegetation to dry out. Lightning from thunderstorms, many of them accompanied by little or no rain, initiated many fires by year’s end. With fire suppression forces few and thinly spaced, the fires spread over vast areas, and lasted for weeks and even months.

Most states were affected, but the largest area burnt was in the Northern Territory (about 45 million hectares, some 33 percent of the total area). Large areas of South Australia and southeastern Western Australia were also burnt (see map). Counting protective burning by graziers in the far north, in all some 117 million hectares (or 15.2 percent) of the continent were burnt. Most of the financial losses were due to damage to fences; stock losses were comparatively light, but loss of fodder due to the fires constituted a more serious problem. More settled areas towards the coast were spared the worst effects, even though vegetation was more dense here. More fire fighting resources, and - fortuitously - relatively few days of strong winds, restricted the spread of fire in these areas. Nevertheless, there were several instances where damage to farms and houses occurred.

Area burnt during the 1974-75 fire-season in Australia (adapted from “Bushfires in Australia”, Luke & McArthur, Aust Govt Printing Service, 1978).