What are bush fires?
A bushfire is a fire that burns in grass, bushland or woodland and can threaten life, property or the environment. A bushfire generally occurs as a result of a build up in fuel and wild weather conditions. Factors that affect the furiously of a bushfire Fuel- The amount of fuel, impacts the rate at wish a bush fire spreads. If the forrest floor is covered in leaves, twigs and dead grasses, the fire will spread at a quicker rate. If the fuel is compacted and tight, the fire will burn hotter. Dry fuel will also burn quicker, whilst damp and moisturised fuels will not as they include hydrogen. Weather conditions- Weather conditions play a critical role in the intensity of a bushfire. If the climate is hot and humid, fire will spread quicker. If the weather is cold, bush fires do not expand at a rapid pace. Most bush fires occur in the afternoon, when the weather, is hot- Wind speed- Wind drives a fire!! By blowing the flames into fresh fuel, the wind increases the intensity of a fire. Wind provides a continuous supply of oxygen. Wind also promotes the rapid spread of fire by spotting, which is the ignition of new fires by burning embers lofted into the air by wind. Spotting can occur up to 30km downwind from the fire front. The width of a fire front also has an influence on the rate of spread. Slope- A bushfire moves faster and gains more speed moving uphill. Going downhill the bushfire moves slower. For every 10 degrees of elevation a slope receives, the bushfire doubles its ferocity. This is why, back burners often burn downhill areas to reduce the fuel supply and intensity of a bushfire. How to protect your property from bush fires 1. Clear leaves from gutters 2. seal any openings under the house or eaves 3. Keep lawns and shrubs trimmed and healthy 4. Install a non-electric-driven sprinkler system that uses water stored in swimming pools, tanks or dams 5. Ensure that hoses are in good order and long enough to reach all parts 6. Wear clothing that is not likely to burn 7. Block downpipes and fill gutters with water and hose down the house if a fire occurs 8. Turn on sprinklers and remove all flammable substances from around the house should a fire occur 9. Place a ladder in the manhole so that you can inspect the roof cavity at regular intervals 10. Make sure that everyone is out of the house should a fire occur 11. Put wet towels against spaces under doors and close blinds, windows and doors should a fire occur 12. Fill buckets, basins and sinks with water to put out spot fires, should a fire occur (referenced from "Australian explorations" by Grant Kleeman) Types of fire-
There are three types of fires; Controlled fires- Controlled burning was first adapted by the aboriginals over 50,000 years ago. A controlled fire is the deliberate burning of fuel, in an effort to reduce the build up of excess burning material Grass Fires- Grass fires are fast moving and contain medium heat levels. The generally burn along the undergrowth of the bush. Bushfires- Bushfires move fast and have a high intensity level. Bushfires generally smoulder for days. The Impacts of Bush Fires Bushfire have social, economical and environmental impacts on communities. Economic Impacts Bushfire's often result in the loss of property, grazing and farming land and even life. The economic effects of a bushfire can be long lasting. Many individuals lose property and their life savings as they are not insured against bush fire. Bushfire's have an annual cost of about 77 million and have claimed nearly 77 million dollars since 1850. The canberra fires in 2003, were particularly disastrous, as it cost the ACT close to a billion dollars. Social Bushfire's cause tremendous stress on communities and individuals. Often homeowners have to choose between leaving their possessions and taking shelter or risking their life to save their properties. Since 1900, 470+173 (Victorian bushfires 2009) lives have been lost to bushfires. There are often many Health impacts resulting from stress and trauma, smoke inhalation and asthma attacks as a result of bushfires. family breakdowns often occur, due to increased pressure. Environmental The Australian environment has evolved with the presence of fire. Most plants have developed adaptations that allow them to regenerate after a fire. Therefore, controlled burning benefits the growth of bushes and forests. Bushfires cause:
“From one small spark a bushfire grows. Sellers of misery are our foes. Merging ruthlessly tongues of flame. Point your finger at those to blame.” Paul Anthony (from the book bushfire)
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Where do bush fires occur in Australia
Australia's climate is hot, dry and humid. Central parts of Australia are particularly at risk of a bush fire. However, coastal and even tropical regions of Australia still receive fires. In southern parts of Australia the bush fire season occurs in summer and autumn. Eastern, coastal regions like NSW and Queensland, receive most bush fires occur in spring and early summer. This is because, grasses in these periods, NSW and Queensland receive have large rainfall periods which grows grass. When the climate dries, the grasses remain long, fuelling the fire. The northern territory receives the majority of its fires in winter and spring. Aboriginals management of fire When the aboriginals settled in Australia, over 50,000 year ago, they adapted to Australia's harsh conditions. They learned to use low-intensity fire to keep the countryside transversal and easy to access. There use of fire also allowed sensitive plants to adapt and regenerate. European settlements bushfire management As europeans removed the aboriginals, regular burning ceased. Bushfire's were tumultuous during the start of European settlement, as they didn't understand that the bush benefited from controlled burnings. European settlements also placed people in areas where the bushfire hazard is the greatest. Europeans also settled on flat land near the sea or along ridges. As bush fires race uphill, ridge top areas are likely to catch on fire. As a result of these actions, bush fires in Australia are intense and often result in the loss of life and livestock. Embers Embers are small pieces of burned material that are carried upwards from the movement of smoke or wind. Even if a fire is put out, embers can still land and trigger a spot fire. Organisations aiding the response to bush fires
There are many organisations that aid the response to bushfires. Government responses Federal government is required to advertise warning and dangers to the community. The federal government is also responsible for implementing fire bans. In an emergency event, federal government ensures all citizens are accurately warned and away from danger. In NSW every local government is required by law to have its own bushfire management community. If a bushfire occurs, the state government is responsible for declaring the rural fire act, which provides additional resources for those people close to the fire.If this act is declared in NSW then the four fire service; the rural fire service, the national parks and wildlife service, state forest service and NSW fire brigade, work in unison to extinguish a fire. There are various independent organisations that provide support for the prevention and after marks of a bushfire. Australia has a fire bridge that includes over 250,000 volunteers. Climate change A global increase in temperature, has resulted in more frequent bushfires. By 2025, fire weather is projected to occur 4 to 5 times more than the modern day. If the global temperature isn't decreased, the climate temperature will increase and bushfire occurrences will become more frequent. Facts
Fire triangle The fire triangle explains how a bushfire occurs. It suggests oxygen. heat and fuel are required for afire to start. In most cases the fuel is undergrowth, the oxygen is provided by the wind and the heat is provided by the day's humidity. |