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AUSTRALIAN NATURAL HAZARDS TASK FORCE
The continent of Australia experiences a range of natural hazards. Natural hazards occur when forces of nature combine to become destructive. All natural hazards present a highly dangerous risk in Australia's communities. In extreme conditions natural hazards impact on communities in many ways, causing damage to property, loss of income to people as well as changing the physical environment.
The Australian Natural Hazards Task Force classify the impacts of natural hazards into 3 main categories.
This information kit created by the Australian Natural Hazards Task Force (ANHTF) will inform you of one of Australia's most common and deadly natural hazard,
This kit will briefly describe what a bushfire is and how it occurs, and gives an in depth account of one of Australia's most horrific bushfires to date, the "Black Saturday Bushfires". Explaining the causes of the hazard, the effects of the hazards on different perspectives and management strategies to reduce the impacts of the hazard in the future.
Bushfires are an intrinsic part of Australia’s environment due to its hot climate, low rainfall and natural vegetation. Australia is frequently devastated by bushfires more so than any other country in the world. There has been a long, dramatic history of bushfires on the continent. Today bushfires wreak havoc across the land causing significant amounts of damage, destroying buildings, houses, harming livestock, impacting the environment and causing death and injury.
Black Saturday Bushfire
A bushfire is a fire that burns out of control spreading across vegetated regions of bush land. In order for a bushfire to be catastrophic, the right conditions must be present. Most bushfires occur at times when temperatures are high and the conditions are dry. Areas with dense undergrowth such as South-eastern Australia, are the most vulnerable to bushfires. Due to the size of the continent and the great diversity of the environmental conditions, there is no time of the year when the entire continent is safe from potential danger of bushfires.
Bushfires in Australia from 1997 - 2008
(NOT TO SCALE)
From 1997 to 2008 this map indicates how many bushfires occured in Australia over those 11 years. Each red triangle represents a single bushfire event.
CAUSES OF IGNITION
A vast majority of bushfires are generated by the actions or influences of humans. Bushfires can be started in a number of ways, for example; leaving a fire unattended (at a camp, barbeque), having an open fire on a windy day, dropping a cigarette or a match that has not been extinguished, leaving flammable chemicals in hot areas or in the sun, farmers burning vegetation on their properties and not administrating it carefully and some fires are lit deliberately by arsonists. These fires can destroy thousands of kilometres of land.
Fire requires three key elements to grow into bushfires and spread. This is referred to as the fire triangle.
These elements are needed for any fire, but in the Australian environment these factors are present in a particularly fatal way.
The three elements are
Australia’s natural vegetation of dry sclerophyll forest and grasslands is prone to fire. The natural oil of the eucalyptus tree located in the tree crown enables fires to combust and spread rapidly in the right conditions. Dry grasslands are another fuel source.
Supply of Oxygen:
The movement of oxygen in the atmosphere is stimulated by strong winds which are caused when steep pressure gradients occur between high and low pressure systems. This occurs a lot in the south-eastern region of Australia during spring and summer. The dry winds that originate from the centre of Australia bring hot dry conditions with them. These winds contribute to fire intensity. Wind changes can also turn small fires into huge fire fronts.
Sunshine and high temperatures dry out the vegetation or fuel source making it susceptible to fire. A succession of extremely hot, dry days over the summer period of Australia adds to the continents fire risk.
BLACK SATURDAY BUSHFIRES
The Black Saturday Bushfires were a series of fires burning across the Australian State of Victoria (15°10'S, 129°40'E) on the 7th of January 2009, during extreme bushfire weather conditions. These fires resulted in Australia’s highest ever loss of life from a bushfire. Black Saturday left many people without homes to live in, and loved ones lost. Communities have had to rebuild their lives after this devastating disaster.
Black Saturday Bushfire Spots In Victoria
ENVIRONMENTAL CAUSES OF THE BLACK SATURDAY BUSHFIRES
The cause of the Black Saturday Bushfires was a mixture of natural and human causes which led to this tragic event. One of the natural causes that contributed to the fires was Australia’s major drought over the last decade. This drought made the land and vegetation dry and an easy fuel source for ignition. Also the week before the fires struck a heat wave travelled through Victoria. This heat wave brought high temperatures of 40 degrees, dry winds blowing over 100km per hour and low humidity. These conditions created more fuel sources consisting of dry vegetation which ignited very easily with heat. This combination of conditions made Victoria very vulnerable to extreme bushfires. The fires destroyed many homes/structures, livestock and lives. In the early evening whilst the fires were still blazing a cool change occurred bringing gale force south-westerly winds as strong as 120km per hour. This change in the wind direction caused the long eastern flanks of the fire to become massive fire fronts that burned towards towns that had earlier escaped the fire.
EFFECTS OF THE BLACK SATURDAY BUSHFIRES
The Black Saturday Bushfires made history by becoming Australia’s highest loss of life with 173 people dead from a single event. The north-east firestorm accounted for 120 deaths out of the 173. Not only did a horrific amount of people die but a devastating number of 414 people were left injured. Over 2030 houses were destroyed,
59 commercial properties (shops, pubs, service stations, golf clubs, etc), 12 community buildings (including 2 police stations, 3 schools, 3 churches, 1 fire station), 399 machinery sheds, 729 other farm buildings, 363 hay sheds,
19 dairies and 26 woolsheds totalling over 3500 structures.
The towns of Kinglake, Marysville and Flowerdale were completely destroyed. The bushfires affected 78 individual townships and displaced 7562 people. Many of the people displaced lived in relief centres, caravan parks or in spare rooms of the houses whist rebuilding was taking place.
Referring to Chart 1, Bushfires have a greater amount of injuries and death tolls over the time period of 1967 - 1999. Also the chart confirms that the costs ($millions) are greater than the other natural hazards. This is because the continent of Australia is hot, humid and dry which makes it vulnerable for bushfires to occur, leaving communities with nothing but dead land for them to rebuild their lives upon.
The total economic cost of this tragedy is estimated to be between $1.02 billion and $1.5 billion. The fires destroyed;
Over 55 businesses
Over 11,000 livestock killed or injured
735 ha (1,820 acres) of fruit trees, olives and vines
168,000 ha (420,000 acres) of pasture
190 ha (470 acres) of standing crops
It also required 3582 fire fighting personnel were deployed to help fight the fires.
The rebuilding of the communities has provided economic benefits such as jobs and work for those within the community and the renewal of facilities and infrastructure.
Fire Fighting Personnel
Fire Fighting Personnel
Referring to chart 2, the state of Victoria has the highest annual cost ($million) for bushfires than any other state and the Northern territory, the lowest.
Referring to chart 3, Bushfires represent 35% of the total insurance losses relating to all natural disasters. This is equal highest with Severe Storms.
Referring to chart 4, on average there is a higher proportion of events with a total economic cost of less than $10m. However the total cost of events <$1om is significantly lower than those >$10m.
The bushfires effected flora and fauna and the surrounding ecosystems;
Approximately 450,000 ha (1,100,000 acres) of bush, agricultural and residential land was burnt.
Fire Fighter Helping Koala
5 of the 9 Melbourne’s major dams were affected by the bushfires, contaminated by the ash and debris. The worst affected being Maroondah Reservoir and O'Shannassy Reservoir.
Millions of animals are estimated to have been killed by the fires.
Of the surviving wildlife, many of them suffered from severe burns. For example many Kangaroo’s feet were severely burnt.
The release of smoke and gases from such a large fire will have have impacted the quality of air in the atmosphere. It was also discovered that smoke from the bushfires was found in Antarctica’s atmosphere.
950 local parks, 70 national parks and reserves, and over 600 cultural sites and historic places were destroyed and
2,150 sheep, 1,207 cattle, and an unknown number of horses, goats, alpacas, poultry and pigs.
Referring to chart 5, Bushfires occurred the 3rd least out of the other natural hazards between the years of 1967 - 1999.
Storms occurred the most.
One of the management strategies that helped the Black Saturday Bushfires were the giant helicopters, called “
that dropped tonnes of water onto the scorching fires, and the generous amount of fire fighting personnel helping fight to put them out.
The two main preventative methods of controlling fires in Australia are;
– involves lighting fires in unburnt areas so that the fire front burns into the areas already burnt.
– lighting low- intensity fires in cooler months of the year during favourable climatic conditions.
These two fire fighting techniques reduce the likelihood of bushfires occurring during the dry season of summer.
As a result of the Black Saturday Bushfires a National Bushfire Prediction, Detection, Simulation and Early Warning System has now been implemented. It will
provide both the public and emergency services in rural, regional and remote Australia with bushfire alerts via SMS and email, instant access to bushfire simulation maps, early warnings of nearby bushfires, testing of bushfire fighting techniques and bushfire prediction tools.
Bushfires can cause lots of damage, so it is essential that individuals respond to the hazard, especially those living in fire prone areas. They should prepare their property before the fire season arrives by following some simple steps such as;
removing leaf litter from gutters
clearing plants from touching the house
keeping grass short and green
fitting shutters to windows and
storing flammable chemicals away from the house
How To Protect A Home From Bushfires
Another essential method to help keep your house and family safe is to have a
Bushfire Survival Plan.
A Bush Fire Survival Plan encompasses the decision to either "Leave Early" or to "Stay and Defend “in the event of a fire, and to make certain that you are prepared and know what to do in the event of a bush fire. The NSW Rural Fire Service has information to help and educate you if you are stuck on what decision to choose and provides you with the advice to help you survive a bushfire.
Also a new planning and building code is being put forward for bushfire prone areas and the new structures have to protect individuals in the buildings/houses up to 817 degrees. Housing is also becoming banned in the highest fire risk areas.
Fire Danger Ratings are spread throughout Australia to warn people of the level of bush fire threat on any given day, based on the forecast weather conditions.
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"Bushfires." Richard Conan-Davies BSc Dip Ed, 26 May 2010. Web. 15 June 2010.
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