Australian Bushfires



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Year 8 Humanities

Geography

http://en.wikipedia.org/wiki/Bushfires_in_Australia
Australian Bushfires

Bushfires in Australia are frequent events during the hotter 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.

Victoria has seen the majority of the deadliest and largest bushfires in Australia, most notably the 2009 Black Saturday fires, where 173 people were killed, around four thousand homes and structured were destroyed, towns were gutted and some such as Marysville were completely destroyed.

Global warming is increasing the frequency and severity of bushfires and will lead to increased days of extreme fire danger

Bushfires in Australia, are generally defined as any uncontrolled, non-structural fire burning in a grass, scrub, bush, or forested area. Australia, being a geographically and meteorogically diverse continent, experiences many types of bushfires. Fires can be divided into two main categories, depending on topography of the area.



  • 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, 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.

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

The natural fire regime in Australia was altered by the arrival of humans. Fires became more frequent, and fire-loving species—notably eucalypts—greatly expanded their range. It is assumed that a good deal of this change came about as the result of deliberate action by early humans, setting fires to clear undergrowth or drive game.

Plants have evolved a variety of strategies to survive (or even require) bushfires or even encourage fire (eucalypts contain flammable oils in the leaves) as a way to eliminate competition from less fire-tolerant species. Some native animals are also expert at surviving bushfires.

In 2009, a standardised Fire Danger Rating (FDR) was adopted by all Australian states. During the fire season the Bureau of Meteorology (BOM) provides fire weather forecasts and by considering the predicted weather including temperature, relative humidity, wind speed and dryness of vegetation, fire agencies determine the appropriate Fire Danger Rating. Fire Danger Ratings are a feature of weather forecasts and alert the community to the actions they should take in preparation of the day. Ratings are broadcast via newspapers, radio, TV, and the internet.



Fire Danger Rating

Category

Fire Danger Index

Catastrophic / Code Red

Forest 100+ Grass 150+

Extreme

Forest 75–100 Grass 100–150

Severe

Forest 50–75 Grass 50–100

Very high

25–50

High

12–25

Low to moderate

0–12

Bushfires in Australia can occur all year-round, though the severity and the "bushfire season" varies by region. These seasons are commonly grouped into years such as "2006-07 Australian bushfire season" and typically run from June one year until May the next year.

In southeast Australia, bushfires tend to be most common and most severe during summer and autumn (December–March), in drought years, and particularly severe in El Niño years. Southeast Australia is fire-prone, and warm and dry conditions intensify the probability of fire. In northern Australia, bushfires usually occur during the dry season (April to September), and fire severity tends to be more associated with seasonal weather patterns. In the southwest, similarly, bushfires occur in the summer dry season and severity is usually related to seasonal growth. Fire frequency in the north is difficult to assess, as the vast majority of fires are caused by human activity, however lightning strikes are as common a cause as human-ignited fires and arson.

Bushfires have accounted for over 800 deaths in Australia since 1851 and the total accumulated cost is estimated at $1.6 billion. In terms of monetary cost however, they rate behind the damage caused by drought, severe stormshail, and cyclones, perhaps because they most commonly occur outside highly populated urban areas.



Some of the most severe Australian bushfires, in chronological order, have included:

Fire

Location

Area burned
1 ha ≈ 2.5 acres


Date

Human Deaths

Properties damaged

1961 Western Australian bushfires

Western Australia

1,800,000 ha

January–March 1961

0

160 homes

Southern Highlands bushfires

New South Wales




5–14 March 1965

3

59 homes

Tasmanian "Black Tuesday" bushfires

Tasmania

Approximately 264,000 ha

7 February 1967

62

1,293 homes

1978 Western Australian Bushfires

Western Australia

114,000 ha

4 April 1978

2

6 buildings (drop in wind in early evening is said to have saved the towns of Donnybrook, Boyup Brook, Manjimup, andBridgetown.)

1979 Sydney bushfires

Sydney, and Region NSW




December 1979

5

28 homes destroyed, 20 homes damaged

Ash Wednesday bushfires

South Australia and Victoria

418,000 ha

16 February 1983

75

about 2,400 houses

Wooroloo Bushfire

Western Australia

10,500 ha

8 January 1997

0

16 homes

Black Christmas

New South Wales

300,000 ha

25 December 2001 – 2002

0

121 homes

2003 Canberra bushfires

Canberra,Australian Capital Territory

160,000 ha

18–22 January 2003

4

almost 500 homes[33]

2003 Eastern Victorian alpine bushfires

Victoria

over 1.3 million ha

8 January – 8 March 2003

3

41 homes

Tenterden

Western Australia




December 2003

2

(2,110,000 ha of forest burnt during the 2002–2003 bushfire season in the S/W of WA)

Eyre Peninsula bushfire

South Australia

145,000 ha

10–12 January 2005

9

93 homes

2006 Grampians Bushfire

Victoria

184,000

January 2006

2

A total of 57 houses, more than 350 other buildings were destroyed.

Dwellingup bushfire

Western Australia

12,000 ha

4 February 2007

0

16

Kangaroo Island Bushfires

South Australia

95,000 ha

6–14 December 2007

1




Boorabbin National Park

Western Australia

40,000 ha

30 December 2007

3

Powerlines and Great Eastern Highway, forced to close for 2 weeks

Black Saturday bushfires

Victoria

450,000+ ha

7 February 2009 –14 March 2009

173

2,029+ houses, 2,000 other structures

Toodyay Bushfire

Western Australia

3,000+ ha

29 December 2009

0

38

Lake Clifton Bushfire

Western Australia

2,000+ ha

11 January 2011

0

10 homes destroyed

Roleystone Kelmscott Bushfire

Western Australia

1,500+ ha

6–8 February 2011

0

72 homes destroyed, 32 damaged, Buckingham Bridge onBrookton Highway collapsed and closed for 3 weeks whilst a temporary bridge was constructed and opened a month after the fires

Margaret River Bushfire

Western Australia

4,000 ha

24 November 2011

0

34 homes destroyed including the historic Wallcliffe House

Tasmanian Bushfires

Tasmania

20,000+ ha

4 January 2013

1

At least 170 buildings

2013 New South Wales bushfires

New South Wales

100,000+ ha

16 October - November 2013

2

As of 19 October 2013 at least 248 buildings destroyed statewide (inc. 208 dwellings), another 109 damaged in Springwood,Winmalee and Yellow Rock

Major fires also occurred in the Hunter, Central Coast, Macarthurand Port Stephens regions causing significant damage.



2014 Parkerville bushfire

Western Australia

386 ha

12 January 2014

1

56 Homes

2014 Grampians Bushfire

Victoria

51800 ha

17 January 2014

1

Fire so intense it created a 12 km-wide convection column, generating its own weather and lightning strikes


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