Southeast Australia

Summer and autumn are the most dangerous times of year in southeast Australia. The highest temperatures occur during these seasons and in most years the grass and forests have dried out by mid-summer.

A typical dangerous fire situation occurs in southeastern Australia when a vigorous cold front approaches a slow-moving high in the Tasman Sea, causing very hot, dry, northwesterly winds. Figure 2 shows the situation associated with the Victorian Ash Wednesday fires of 16 February 1983. The passage of the cold front can cause the winds to suddenly change direction, shifting fire direction abruptly.

Fires driven by a strong, steady wind are usually long and narrow. When the wind changes with the passage of a cold front, the long side of the fire can suddenly become the fire front.