Geography Notes Year 9 - Bushfires

BUSHFIRES – VIVIANNA IP YR 10

- Bushfire: the combustion or burning of bush, forest or woodland area.

- They occur because of Australia's hot, dry climate and the fact that Australia experiences many droughts.

- South-eastern Australia includes areas that are prone to the most severe and frequent bushfires in the world.

- Strong winds in summer and sudden changes in wind direction can worsen the damage that bushfires cause.

- Occur in areas where major forests are found.

- Many of Australia's native plants burn easily – eucalyptus trees have a high oil content and are highly flammable, the large area of dry grass common in mid to late summer also burn readily.

- Can be caused by natural means (lightning strikes) or by humans who act carelessly.

- It can either be controlled or can burn out of control (depending on weather conditions – wind, the quality and the dryness of the undergrowth).

- 4 main factors that lead to the right climatic conditions for bushfires are:

1. Humidity ( the amount of water vapour present in the atmosphere): very low humidity (less than 20%) causes fuel to dry out and become flammable.

2. Lack of rainfall: leads to dry vegetation, dead leaves and twigs that become fuel for bushfires.

3. Wind: air movement provides the oxygen the fire needs to keep burning; stronger winds bring more oxygen and stronger flames and winds also blow small fragments of ignited vegetation (embers) downwind causing small fires and burnt-out areas (spotting).

4. Temperature: hot air can lower the moisture content of vegetation.

ECONOMIC IMPACTS

Total cost of fire approx $8500million/annum (approx 1.15% of AUS. GDP)

- Many individuals lose property and their life savings, as they are not insured against bushfires.

SOCIAL IMPACTS

- Approx. 100 fatalities + 3000 injuries/ average each yr.

- Loss of homes average 83 homes a year.

- Health impacts resulting from stress, smoke inhalation and asthma attacks.

- Many individuals have a poor understanding of the risks posed by bushfires and how to preserve their lives and property and as a result may be traumatised.

ENVIRONMENTAL IMPACTS

- Broad range of impacts in the biophysical environment.

- Create

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