Bushfires in Australia

Looking towards the town Swifts Creek, Victoria, in December 2006 during the Victorian Alpine Fires
Intense bushfires can seriously impact the environment, such as here by the Big River, near Anglers Rest, East Gippsland, after the 2003 Victorian fires

Bushfires are frequent events during the warmer months of the year, due to Australia's mostly hot, dry climate. Each year, such fires impact extensive areas. On one hand, they can cause property damage and loss of human life. On the other hand, certain native flora in Australia have evolved to rely on bushfires as a means of reproduction, and fire events are an interwoven and an essential part of the ecology of the continent. For thousands of years, Indigenous Australians have used fire to foster grasslands for hunting and to clear tracks through dense vegetation.

Major firestorms that result in severe loss of life are often named based on the day on which they occur, such as Ash Wednesday and Black Saturday. Some of the most intense, extensive and deadly bushfires commonly occur during droughts and heat waves, such as the 2009 Southern Australia heat wave, which precipitated the conditions during the 2009 Black Saturday bushfires in which 173 people lost their lives. Other major conflagrations include the 1983 Ash Wednesday bushfires, the 2003 Eastern Victorian alpine bushfires and the 2006 December Bushfires.

Global warming is increasing the frequency and severity of bushfires. [1]

Categories

The term "bushfire" builds on the concept of " the bush", referring to sparsely-inhabited regions. Bushfires in Australia are generally defined as uncontrolled, non-structural fires burning in a grass, scrub, bush, or forested area. Australia, being a geographically and meteorogically diverse continent, experiences many types of bushfires. There are two main categories, depending on local topography.

  • Hilly/mountainous fires – burn in hilly, mountainous or alpine areas which are usually densely forested. The land is less accessible and not conducive to agriculture, thus many of these densely forested areas have been saved from deforestation and are protected by national, state and other parks. The steep terrain increases the speed and intensity of a firestorm. Where settlements are located in hilly or mountainous areas, bushfires can pose a threat to both life and property.
  • Flat/grassland fires – burn along flat plains or areas of small undulation, predominantly covered in grasses or scrubland. These fires can move quickly, fanned by high winds in flat topography, and they quickly consume the small amounts of fuel/vegetation available. These fires pose less of a threat to settlements as they rarely reach the same intensity seen in major firestorms as the land is flat, the fires are easier to map and predict, and the terrain is more accessible for firefighting personnel. Many regions of predominantly flat terrain in Australia have been almost completely deforested for agriculture, reducing the fuel loads which would otherwise facilitate fires in these areas.

Common causes of bushfires include lightning, arcing from overhead power lines, arson, accidental ignition in the course of agricultural clearing, grinding and welding activities, campfires, cigarettes and dropped matches, sparks from machinery, and controlled burn escapes.

Looking towards Dargo, Victoria from Swifts Creek, 11 January 2006