Hazards, Disasters and Survival

A booklet for Students and the Community

Chapter 2

Wildfire Hazards and Disasters

AUSTRALIAN WILDFIRES (BUSHFIRES)

Every summer, Australia has a large number of wildfires (which we call bushfires), usually caused by lightning or humans. Most are not disasters, however, if not quickly detected and extinguished, even a small fire can get out of control and possibly cause a disaster.  In drier seasons the danger is much higher, and all too quickly bushfires can become large, spreading to threaten human life, homes and other buildings, crops, livestock, forests and wildlife.

Bushfire Disasters

Bushfire is one of the most destructive forces of nature.  Fire-fighters, both professional and volunteer, risk their lives each year to control and eventually extinguish them.  Most of Australia’s most devastating bushfires have happened where they have raged through dense eucalypt forests into the suburban fringes of major cities.  Thankfully, few bushfires earn the title of ‘disasters’, but repeated disastrous bushfires near each capital city in Tasmania, South Australia, Victoria and New South Wales have occurred, in which many people have lost their lives, or their homes and property.  The worst of these were: Victoria, 1939 (Black Friday) - 71 dead; southern Tasmania, 1967 (including Hobart) - 62 dead; New South Wales, 1968 (Blue Mountains and coastal) - 14 dead; southern Victoria, 1969 - 23 dead; and South Australia and Victoria, 1983 (Ash Wednesday) - 76 dead.  Bushfires in Australia occur as either ‘grass fires’ or ‘forest fires’.

Grass Fires  -  These occur mainly on grazing, farming or remote scrub country.  Although they often destroy fences, livestock and some buildings, they rarely result in heavy loss of human life.

Forest Fires  -  Under adverse weather conditions, wildfires in Australian eucalyptus forests cannot be stopped and often destroy homes and settlements which border such areas.  Huge amounts of flammable eucalyptus vapour, transpired from leaves, create fireballs which often engulf the forest upper storey ahead of the main fire-front.  Clouds of dense smoke can mask the fire-front from both ground and aerial observation, making it even more difficult to attack the fire.  During the Ash Wednesday fires in 1983, aircraft with infra-red heat-sensing equipment were needed to locate and plot some obscured fire-fronts.

South-eastern Australia has the greatest wildfire hazard in the world.  Bushfires are driven by strong, hot north-westerly winds.  Long fire-flanks often suddenly become fire-fronts when south-westerly wind changes occur.  Therefore  timely, accurate weather information is vital for fire-fighting teams.  Really large bushfires, however, burn until stopped naturally by rain or lack of fuel, which may be weeks after ignition.

Control Techniques

Bushfires are usually fought by numerous trained volunteers and a core of professional fire-fighters with vehicle-mounted equipment (in accessible terrain).  Observation is often provided by light aircraft and helicopters.  In small bushfires crop-dusting aircraft using water or retardants are often effective in saving farm houses and facilities.  Water-bombing is also provided by helicopters with buckets which lift water from dams, lakes or swimming pools.  They are effective in stopping spot fires ignited by windborne firebrands, sometimes kilometres ahead of the main fire-front.  This greatly assists and contributes to the safety of fire-fighting crews.  Larger aircraft are rarely used because of limited nearby water supplies, long turn-around times, and poor cost-effectiveness.  In large bushfires, bulldozers and graders are used to create emergency firebreaks ahead of fire-fronts.  Back-burning from firebreaks is frequently effective in slowing or stopping the spread of fire.

Prevention and Reduction

In some communities, local government authorities have regulations controlling home-siting, design and building materials in bushfire-prone areas.  Wide firebreaks along property boundaries must be maintained and fuel reduction (controlled) burning is carried out during the cooler seasons.

The risk of a bushfire occurring can be reduced if people take a little more care and use common sense when dealing with fire or materials that can ignite easily. A carelessly thrown cigarette butt, or a campfire not properly extinguished, are just two common causes of fires.  Your local fire authority would be happy to give you more detailed information about fire safety and prevention.  Bushfire survival and property protection information appears at the end of this chapter.

OTHER COUNTRIES

Overseas, wildfires are either known by this general term or as forest fires or brush fires.  They are less common and generally much less severe than bushfires in Australia, rarely causing heavy loss of life or homes.  However, serious ones have occurred in the USA (mainly California), southern Europe, Indonesia and China.

AUSTRALIAN BUSHFIRES  -  CASE STUDIES

1.         South Australia and Victoria  -  ‘Ash Wednesday’, 1983

Conditions for Disaster  - On 16 February 1983, Melbourne was experiencing a very hot, dry day.  The temperature peaked at 43°C with relative humidity of only 6%.  Drought conditions had persisted in south-eastern Australia for several years with 1982/83 summer being extremely hot and dry.  Many small to moderate bushfires occurred in South Australia and Victoria over this period.  Fires burnt over 100,000 hectares near the New South Wales/Victoria border on 1 February.  On 6 February, 95 fires were reported as they flared in hot, strong, north-westerly winds.  By 16 February, ‘Ash Wednesday’, South Australia and Victoria were tinder dry and fuel loads in forests were very high.

The Toll  -  In the twenty-four hours following that morning, a holocaust of bushfires erupted, and in just a few  days, burnt over 520,000 hectares across the two States.  More than 3,700 buildings were destroyed, including 84 commercial, and about 1,000 farms.  A total of over 2,400 families or individuals lost their homes while 76 people died!  Many of the total 1,100 injured people required hospital treatment (map shows worst-affected areas).  Livestock losses were very high, with over 340,000 sheep and 18,000 cattle, either dead or having to be destroyed, while 20,000 km of fencing and 1.5 million hay bales were burnt.  During that summer of 1982/83, at least 1 million hectares were burnt out across South Australia and Victoria.  Insurance losses exceeded $320 million and total estimated costs were $950 million in 1997 values.

2.         New South Wales - Eastern Seaboard, 1994

Relentless Westerlies - In early January 1994, hot, dry, westerly winds began to blow from the inland affecting most of the east coast of the State.  Several large bushfires broke out in the north.  These were soon followed by serious outbreaks all along the coast extending to the south of Batemans Bay (see satellite photo). Dangerous winds persisted for about three weeks resulting in over 800 bushfires.  The most serious fires were in the Hunter, Blue Mountains and Sydney regions.  About 20,000 volunteer fire-fighters (including reinforcements from all states and territories) battled the flames and helped evacuate over 25,000 people from areas under serious threat.

Losses and Costs  - About 800,000 ha burnt, including sections of Sydney suburbs and 40 National Parks.  Four deaths (including 3 fire-fighters) resulted, 120 people were injured and 800 people were left homeless after 205 homes and about 20 other buildings were destroyed.  Only 200 livestock died but 600 km of fencing and thousands of native animals perished.  Insurance losses were $56 million with total costs estimated at $165 million (1997 values).

3.            Mornington Peninsula and Dandenong Ranges-Victoria, 1997

Heatwave Conditions  - Temperatures soared above 40°C as northerly winds gusted to 70 kmh contributing to two damaging bushfires near Melbourne between 19 and 21 January 1997.  At Mt Eliza two homes burnt and evacuations were required at Mt Martha and Arthur’s Seat, also on the Mornington Peninsula.  250 bushfires burnt areas of Victoria on 21 January, a 41.2°C day!  Worst-affected were Ferny Creek, Upwey and Kalorama settlements in the Dandenong Ranges where it took 1,500 fire-fighters and 6 water-bombing aircraft to control the 3,700 ha forest blaze.

The Toll  - Apart from Mt Eliza, another 41 houses were destroyed and 45 damaged in the Dandenongs.  Tragically, three people died (at Ferny Creek) and about 40 were injured throughout the State.  Insurance losses were about $10 million with total estimated costs of $40 million (1997 values).

BUSHFIRE SURVIVAL AND PROPERTY PROTECTION

There are many factors which affect the risk to life and property.  These include property location and access, the amount and type of nearby vegetation, building position and condition, availability of water and the physical capabilities of those  involved.  In bushfires, radiant heat, dehydration and asphyxiation (choking) are the major killers.  Well-prepared houses resist the normally-brief exposure to bushfire flames, protecting those inside who may then be able to save their homes.

Preparation Before the Bushfire Season

u            If possible, make a firebreak around your home (use mower, spade, rake), trim branches well clear of house.  Clear roof gutters of leaves, twigs etc.

u         Store wood, fuel, paints etc well clear of the house.

u            Remove rubbish, leaf litter and native shrubs close to house.  Keep grass short/green.

u         Fit wire screens to doors, windows, vents. Enclose gaps, roof eaves and under house.

u         Keep a ladder handy for roof access (inside and outside) and hoses to reach all parts of house and garden.  If water is not connected, obtain a high pressure pump.

u         Decide on a household plan to either leave early or stay to protect your properly-prepared home during a bushfire (see overleaf). Check you have bushfire insurance.

If a Bushfire Approaches

If you prepare your house as noted above, and unless you decide to leave early or have been ordered by authorities to do so, stay in the house after taking these extra precautions:

u         Phone the bushfire brigade - do not assume they know about the fire.

u         Fill baths, sinks, buckets etc with reserve water and turn off gas and power.

u            Remove curtains and move furniture away from windows.

u         Wear long woollen or heavy cotton clothes and solid boots or shoes, a hat or woollen balaclava and gloves.

u         Plug downpipes with rags and fill all roof gutters with water.  Hose down walls, garden, etc on the sides of the house facing the ‘fire-front’ and watch for spot-fires.

u         Inside, close all windows, doors and block crevices and gaps.  When the fire-front arrives, stay inside, away from windows, while it passes (usually 5 to 15 minutes).

u         Quickly extinguish any fires which may have started in, on, or under the house and  check inside the roof cavity as well.

u         If the house is alight and can’t be extinguished, move away to safe burnt ground.  Don’t leave the area, wait for help. Listen to the battery radio for official information.

If Caught in a Bushfire while Driving - Stay in the Vehicle

u         Don’t drive in or near bushfires. If caught in one don’t drive through flames or smoke.

u         Stop at a clearing or by the roadside in a low vegetation area.  Switch off ignition, and turn on hazard lights and headlights.

u         Stay inside unless near safe shelter.  Keep vents, windows and doors closed.  Lie down below window-level, under a woollen blanket until the fire-front passes.

Research shows that in a bushfire, a car petrol tank is unlikely to explode in the period needed to stay inside the vehicle using it as a shield against deadly radiant heat of the fire-front.

If Caught in a Bushfire on Foot

u         Don’t panic  - cover all exposed skin.  Move across-slope, away from the fire-front, then down-slope towards the rear of the main fire.  Find open, or already burnt ground.

u         Do not try to out-run the fire or run uphill or go through even low flames unless you can clearly-see a safe area close-by.

u         If you can’t avoid the fire, protect yourself from heat radiation by lying face down  under an embankment, rock, loose earth, or in a hollow, or if possible get into a pond, dam or stream - but not  into a water tank.

Vital Points to Remember

If you are in a house or car you will be safer than in the open while the fire-front passes.  Stay there, unless advised to leave by emergency authorities. If caught in the open you must protect yourself from the radiant heat of flames by every possible means.

Note:  A heavy, pure wool blanket (to wrap around you) and a flask of water (to drink and to moisten a corner of the blanket as a smoke mask) are basic requirements for bushfire survival and will give protection against radiant heat, dehydration and asphyxiation even in intense fires.

STUDENTS - FIND FURTHER INFORMATION

As a project on bushfires, find out more about:

u         causes of bushfires and how they spread, or bushfire prevention and control;

u         Hobart, Tasmania, 1967;

u         Black Friday, 1939; and

the effects of radiant heat, dehydration and asphyxiation.

	EMERGENCY MANAGEMENT AUSTRALIA, PO Box 1020 Dickson, Australian Capital Territory  2602, AUSTRALIA Telephone: + 61 (0) 2 6266 5402    Facsimile: +61 (0) 2 6266 5029    Email: ema@ema.gov.au AUSTRALIAN EMERGENCY MANAGEMENT INSTITUTE, Mount Macedon Road, Mount Macedon, Victoria  3441, AUSTRALIA Telephone: + 61 (0) 3 5421 5100    Facsimile: +61 (0) 3 5421 5272    Email: aemi@ema.gov.au
	This page was last updated May 31, 2001