FEATURE ARTICLE 4: NATURAL DISASTERS IN AUSTRALIA

'Mother Earth can seem like an uncaring planet. The impact of geohazards on our lives and economy is very great, and will never go away. Every year floods, tsunamis, severe storms, drought, wildfires, volcanoes, earthquakes, landslides and subsidence claim thousands of lives, injure thousands more, devastate homes and destroy livelyhoods'. International Union of Geological Science (IUGS), last viewed August 2007, <http://www.esfs.org>.

The following survey of natural disasters occurring within Australia since the late-19th century, first published in the article A hundred years of science and service - Australian meteorology through the twentieth century in Year Book Australia 2001, has been expanded and updated.


Federation drought 1895-1902

The five years preceding Federation had been intermittently dry over most of the country. Very dry conditions set in across eastern Australia during the spring of 1901, and became entrenched over the following months. As the drought worsened, enormous sheep and cattle losses were reported from Queensland, and many rivers dried up. The Darling River at Bourke virtually ran dry, while Murray River towns such as Mildura, Balranald and Deniliquin - at that time dependent on the river for transport - suffered badly. The Australian wheat crop was all but lost. Rain in December 1902 brought temporary relief, with a more substantial break in autumn 1903. The long drought and its severe climax in 1902 had devastated stock numbers, and began focusing attention on planning for irrigation, especially in the three states through which the Murray River flows.


Cyclone - Mackay - January 1918

The Mackay Cyclone was the first of two cyclones to inflict heavy damage on significant population centres in northern Queensland during early 1918. Moving in from the Coral Sea late on 20 January, its devastating winds terrified residents as buildings disintegrated, gas and water supplies failed, and roofing iron scythed though the air. A storm surge inundated the town around 5.00 am, with large waves reportedly breaking in the centre of Mackay. Phenomenal rainfall - 1,411 millimetres (mm) in three days at Mackay Post Office - generated the worst flooding in Mackay's history. In total, 30 people lost their lives, mainly in Mackay and Rockhampton.

Floods - north-eastern Tasmania - April 1929

Although north-eastern Tasmania's climate is normally relatively benign, it is prone to intense rainfall over short periods. The worst event of the 20th century occurred in April 1929, when 22 people died. Rain commenced late on 3 April and, in three days, up to 500 mm fell over the high country of the north-east, and over a smaller area south of Burnie and Ulverstone. The Briseis Dam on the Cascade River crumbled, and the resulting torrent, carrying thousands of tons of trees, rocks and gravel, overwhelmed houses and offices, with 14 deaths. Over 1,000 houses in Launceston were inundated, and most other north coastal rivers were heavily flooded. Scenes of devastation - to man-made structures and natural features - were widespread across northern Tasmania.


Bushfire - Victoria - Black Friday, January 1939

Following an exceptionally dry winter and spring, vegetation over most of Victoria was in an extremely hazardous condition by January 1939. Heatwave conditions from early in the second week of January saw many large fires break out, especially on the 10th when Melbourne registered a maximum of 44.7 degrees Celsius (^oC). Despite milder conditions in southern Victoria on the 11th and 12th, the fires could not be extinguished and 21 people died. On the 13th the onset of strong and even hotter winds (Melbourne a record 45.6^oC) coalesced these fires into a sea of flame. Several timber towns were burnt to the ground, extensive tracts of mountain forest (including Melbourne's main catchment area) were incinerated, and 50 more people died, many trapped in timber mills. In the ensuing Royal Commission, many changes to rural fire fighting practices in Victoria were proposed, and eventually implemented.


Record floods - New South Wales - February 1955

The Hunter Valley floods of late February 1955 have, in many people's minds, come to symbolise flooding in Australia. A monsoon depression moving south from Queensland deposited up to 250 mm of rain in 24 hours over the already-saturated Hunter region. The Hunter, and several west-flowing rivers, swiftly rose to record levels, drowning the surrounding country. In East Maitland, water completely submerged houses, and 15,000 people were evacuated. It was a similar story throughout the Hunter, Macquarie, Namoi and Gwydir River Valleys, with houses destroyed, metres of flood waters in the streets, and many thousands of stock drowned. In all, 14 people died, and damage to bridges, roads, railways and telephone lines took months to repair. This event was the most spectacular of many heavy rain episodes over eastern Australia between late-1954 and the end of 1956.


Fire and storm - south-west Western Australia - 1961, 1978

Perhaps Western Australia's worst bushfire disaster - the Dwellingup fires - occurred in January 1961. An intense cyclone off the north-west coast led to five days (20-24 January) of gusty winds and 40^oC temperatures over the lower south-west. Fires, many started by lightning, burnt uncontrolled through this period. Strong north-west winds on the 24th drove the fires southward, destroying the township of Dwellingup, and many houses in other small settlements. Fortunately there was no loss of human life. A similar event occurred in early April 1978, when Cyclone Alby swept past the south-west of Western Australia, generating severe gales (gusts to 150 kilometres per hour (km/h)) between Kalbarri and Albany, and causing widespread damage and coastal (storm surge) flooding, as well as raising large dust clouds. Over 360 separate fires flared, more than 114,000 hectares (ha) of forest and farmland were burned, and many buildings and homes destroyed.


Bushfire - southern Tasmania - Black Tuesday, February 1967

On Tuesday 7 February 1967, 110 fires fanned by 80 km/h winds ravaged southern Tasmania, burning within a 56 km radius of Hobart and reaching to within 2 km of central Hobart. Over the four days leading up to the fires, a period of extreme temperature (around 40^oC) and low humidity was experienced. The fire index of 96 on the day of the fire was one of the highest readings on record and there were winds of up to 65 knots. A wet spring had produced thick, lush vegetation, which became very dry in the three months prior to the disaster, resulting from the warm temperatures that prevailed. The main vegetation types found in this area were rainforest and eucalypt forest as well as cleared land. There were 62 deaths, 900 injuries and over 7,000 people made homeless. The fires killed 500 horses, 1,350 cattle, 60,000 sheep, 24,000 chickens, 600 pigs, and other animals. Around 3,000 buildings - 1,293 homes, 128 major buildings including factories, churches, schools and post offices - 80 bridges, and 1,500 vehicles were destroyed. In total, 5,400 km of farm fences and 265,000 ha were burnt, including orchards - 20% of Tasmania's fruit crop - other crops, pastures and forests. The total estimated cost of the fires at the time was approximately $45 million (m) and insurance loss was $14m.


Earthquake - Meckering -
October 1968

Although the Meckering earthquake was not the largest in Western Australia's history, it was certainly the most significant in terms of damage done (over $5m) and cultural upheaval. At 10.59 am, on 14 October 1968, the small wheat-belt town of Meckering, about 130 km east of Perth, was destroyed by an earthquake. From the population of approximately 240 people, 20 were injured, but incredibly, no one was killed. The earthquake was felt throughout the southern half of the state and caused damage in the surrounding townships, particularly York and Northam, and in the Perth metropolitan area. It measured 6.9, making it one of the largest recorded seismic events in Australian history. The earthquake, and its aftershocks, were accompanied by surface faulting extending over an area of 200 square kilometres (sq km). Some of the surface faulting - up to 3 metres high and nearly 40 km long - is still visible today. The Meckering Fault was the first tectonic ground breakage to be recorded in Australia.

Floods - Brisbane - January 1974

Following a very wet 1973, the month of January 1974 featured probably the biggest continent-wide drenching since European settlement, with vast areas of the country inundated. In Brisbane, preceding heavy rain had already produced some flooding when, on 24 January, Cyclone Wanda came ashore north of the city. Wanda inflicted relatively little wind damage, but produced record rains over the Australia Day weekend. In three days, Brisbane received 580 mm, with much higher falls over river catchments near the city (1,300 mm in five days at Mt Glorious). Many houses bordering rivers and creeks were washed away as rivers rose to their highest levels since the disastrous 1893 floods. The rising waters trapped people in homes and offices causing many heroic rescue attempts but unfortunately 14 people died.

Cyclone Tracy - Darwin -
December 1974

The year 1974 started with Cyclone Wanda bringing devastating floods to Brisbane, and ended with Darwin devastated by Cyclone Tracy. Small but compact by world standards, Tracy packed unusually strong winds (gusts to 217 km/h at Darwin Airport before the recorder failed). Tracy moved in from the Arafura Sea, skirted Bathurst Island, then, swinging sharply south, struck Darwin early on Christmas Day. Good warnings had been issued, but the combination of public indifference (it was Christmas and no severe cyclone had affected Darwin for years), extremely fierce winds, and the loose design of many buildings at that time, led to wholesale destruction. Most buildings were totally destroyed or badly damaged and 65 people died. Much of the remaining population was swiftly evacuated. In the wake of Tracy, much more attention was given to building codes and other aspects of disaster planning.

The 1982-83 drought

In terms of short-term rainfall deficiencies (up to one year) and their impacts, the 1982-83 drought was probably Australia's worst in the 20th century. It started in autumn 1982, with severe rainfall deficiencies over eastern Australia exacerbated by frequent sharp frosts in June and July. Dry conditions persisted, and by year's end extensive areas of eastern Australia had record or near-record low April to December rainfall. The upper Murrumbidgee River became a chain of waterholes. Reservoirs throughout the south-east fell to levels unknown for many years. The northern Australian wet season failed, with record low summer rain in some areas. In February 1983, dust storms and devastating fires swept the south-eastern States, before heavy rain in late March broke the drought. In all, this drought caused losses in excess of $3 billion (b), and first brought into public prominence the link between El Niño and Australian drought.


Dust storm - Melbourne -
February 1983

Late on the morning of 8 February 1983 a strong, but dry, cold front began crossing Victoria, preceded by hot, gusty northerly winds. The loose topsoil in the Mallee and Wimmera was quickly picked up by the wind, and as the front moved east, the soil collected into a large cloud oriented along the line of a cool change. At Horsham, in western Victoria, raised dust could be seen by 11.00 am; by noon it had obscured the sky. In Melbourne, the temperature rose quickly as the north wind strengthened, and by 2.25 pm it had reached 43.2^oC, a record February maximum. A short time later, a spectacular reddish-brown cloud could be seen advancing on the city, reaching Melbourne just before 3.00 pm. It was accompanied by a rapid temperature drop, and a squally wind change strong enough to uproot trees and unroof about 50 houses. Visibility plunged to 100 metres. The worst of the dust storm was over by 4.00 pm, when the wind speed dropped rapidly. At its height, the dust storm extended across the entire width of Victoria. The dust cloud was up to 320 metres deep when it struck Melbourne, but in other areas extended thousands of metres into the atmosphere. It was estimated that about 50,000 tonnes of topsoil were stripped from the Mallee - about a fifth was dumped on the city - leaving the ground bare, and exacerbating the effects of the drought. Open water channels in the north-west were clogged with sand and dirt.


Bushfire - South Australia, Victoria - Ash Wednesday, February 1983

The severe drought over eastern Australia in 1982 led to tinder dry conditions throughout the grasslands and forests of south-eastern Australia. On 16 February 1983, near-gale force northerly winds, and temperatures well over 40^oC drove huge fires (many started by arsonists) across Victoria and south-eastern South Australia. Nearly 2,500 houses were destroyed and 75 people died (47 in Victoria and 28 in South Australia). The worst affected areas were Victoria's Dandenong Ranges and the Macedon area, and South Australia's Mt Lofty Ranges, all scenic areas with considerable residential populations. Forests in south-eastern South Australia and Victoria's Otway Ranges were incinerated. Most deaths occurred in the hour following the cool change, when strong, gusty westerly winds turned long, narrow corridors of flame into wide fronts. The enquiry that followed led to many changes in fire weather briefing procedures, most notably the provision for regular updates on the progress of wind changes.

Tropical cyclones - Port Hedland

The Pilbara coast in Western Australia experiences more cyclones than any other part of Australia. Since 1910 there have been 48 cyclones that have caused gale-force winds at Port Hedland. On average this equates to about one every two years. About half of these cyclones have an impact equivalent to a category 1 cyclone. Six of these, January 1939, March 1942, Cyclone Joan in December 1975, Cyclone Leo in March 1977, Cyclone Dean in February 1980, and Cyclone Connie in January 1987 caused very destructive wind gusts in excess of 170 km/h. Along the Pilbara coast the cyclone season runs from mid-December to April peaking in February. The strongest wind gust recorded at Port Hedland during a cyclone is 208 km/h during Cyclone Joan (1975).


Earthquake - Newcastle - December 1989

At 10.27 am on Thursday 28 December 1989, the city of Newcastle, New South Wales was devastated by a moderate earthquake of magnitude 5.6. The epicentre, approximately 15 km south-east of the Newcastle central business district, was 10-12 km deep within the crust under Boolaroo, an outer suburb of Lake Macquarie. The effects were felt over an area of about 200,000 sq km, with isolated reports of movement from up to 800 km from Newcastle. An aftershock, measuring 2.1, was recorded the following day. The earthquake claimed 13 lives and 160 people were hospitalised. Nine people died at the Newcastle Workers Club; three people were killed in Beaumont Street, Hamilton and one person died of shock. Damage to buildings and facilities, totalling about $4b, occurred within a 9,000 sq km region. Approximately 50,000 buildings sustained damage, including 40,000 homes, affecting 300,000 people and leaving 1,000 homeless. A further 300 buildings were demolished. Some of the buildings in Newcastle dated back to the 1860s, most of them were either unreinforced masonry (URM) or had URM components such as chimneys, walls, verandahs or access stairs. Over the years, pollutants had caused widespread corrosion of steel ties in homes and other buildings, and in the suspension ties of awnings and parapets, where they existed. As a result all such buildings were highly vulnerable to horizontal shaking. Additionally, foundation soils in the Newcastle area played a key role. In the inner parts of the city these were alluvium, some of it dredged from the Hunter River, other parts were underlain by former courses of the river now filled either naturally over time or for housing developments. Ground shaking on sedimentary layers may be amplified relative to that on bedrock at frequencies which correspond to the natural frequencies of buildings so damage is exacerbated.


Landslide - Thredbo - July 1997

At 11.35 pm on Wednesday 30 July 1997, 2,000 cubic metres of mud and rock shifted below the Alpine Way, a main road above the village of Thredbo in the New South Wales Alpine Region. The slide travelled down the slope taking with it the Carinya Ski Lodge. It then tumbled down the hill across Bobuck Lane, slamming into an elevated car park and then directly into Bimbadeen Lodge. Large parts of both buildings were scattered across the site and buried under 3,500 tonnes of rubble and soil; 18 people were killed. The area of landslide had a slope of between 22 and 40 degrees, composed primarily of soil and some loose or floating boulders. Rescue strategies were developed collaboratively by the emergency services, coordinated by New South Wales Police. The harsh environment, steepness of the hill and instability of the site made rescue operations difficult. The instability of the site under darkness posed danger to emergency services personnel and rescue could not begin until daylight. It was only after initial assessments were made of the collapsed structure that effective search methods could be carried out to detect the location of trapped victims. Only then was drilling through slabs and inserting cameras possible. Approximately 1,100 individual pieces of equipment were used on site by New South Wales firefighters. At 5.50 am on Saturday, 2 August a male survivor, Stuart Diver, was found in a confined space trapped under three concrete slabs. Although suffering from hypothermia he was not severely injured. His release took rescuers and paramedics more than ten hours. Seven years later a New South Wales Supreme Court judgement determined the cause as 'a leaky mains pipe and a road built on a vulnerable slope of debris'. Since the landslide, the New South Wales Government has spent $50m upgrading the Alpine Way.

Storm at sea - Sydney to Hobart yacht race - December 1998

Of the 115 yachts that set sail at 1.00 pm on 26 December 1998 in the Sydney to Hobart yacht race, only 44 reached their destination. The cause of this disaster was an intense low pressure system which formed in the Bass Strait region of south-eastern Australia during the long weekend of 25-28 December 1998. The explosive development of this low commenced on 26 December and reached peak intensity on 27 December with average wind speeds reported in the 50-60 knot range. Gusts and squalls of considerably higher wind speeds would almost certainly have been experienced by the yachts for short periods - possibly reaching up to 70-75 knots - and causing ferociously massive seas. The destruction caused to the fleet by the storm triggered a huge search and rescue operation involving numerous personnel from organisations such as the Australian Maritime Safety Authority, the Royal Australian Navy, the Royal Australian Air Force and police. Even so, it resulted in the abandonment of several yachts and the death of six people. It was the most disastrous event in the then 54-year history of this yachting classic. The yachts encountered very severe wind and sea conditions before most were half way into their approximately 630 nautical mile journey down the south-east coast of Australia. The worst weather to hit the fleet occurred off the southern New South Wales coast and in eastern Bass Strait. The Bureau of Meteorology had issued a gale warning for the southern New South Wales coast four hours in advance of the start of the race; it upgraded this to a storm warning for the southern New South Wales coast and the eastern Bass Strait area about one hour into the race.


Record rainfall - Esperance - January 1999

The following extract is from the Western Australian Regional Office of Climate and Consultative Services, Bureau of Meteorology records for 7 January 1999:

'Persistent heavy rainfall in the Esperance region in the past few days has caused significant flooding. From late Monday evening (4th) until 9.00 am today Esperance recorded 209 mm, the heaviest rainfall event since rainfall records began in 1889. A total of 107 mm fell in the 24 hours to 9.00 am this morning, including 55 mm from 10.00 am until 11.30 am yesterday morning. This is the third highest daily fall on record, falling short of the 126 mm on 30 April 1922. The two-day fall of 189 mm replaces the previous highest total of 137.7 mm on 5-6 June 1941. This unseasonal event is due to a strong and slow moving upper level trough undercut by cool south-easterly winds near the surface.'


Hailstorm - Sydney - April 1999

New South Wales and southern Queensland are particularly prone to large hail, normally accompanying severe thunderstorms developing along low pressure troughs. Late on 14 April 1999, a storm moving parallel to, and just off the southern New South Wales coast, swung north over the eastern suburbs of Sydney. Huge hailstones, some the size of softballs, and driven by squally winds, struck the city and eastern suburbs. The onslaught of ice badly damaged or destroyed many cars, partly destroyed many homes, and damaged several commercial aircraft. Many thousands of buildings, mostly homes, suffered serious roof damage. Insurance losses exceeded $1.7b, replacing the Newcastle earthquake of 1989 as Australia's costliest natural disaster (in terms of insured losses).

Bushfire - Canberra -
January 2003

In mid-January 2003, due to the combination of extreme weather conditions (high temperature, low humidity, lightning strikes and strong gusty winds) multiple bushfires broke out in the Kosciuszko National Park, New South Wales and the Namadgi National Park, south of Canberra, Australian Capital Territory. During the ensuing days, gale-force winds pushed the fires into the forested land adjoining Canberra, including the Stromlo forest. During the afternoon of Saturday 18 January the situation deteriorated quite dramatically, with fire spreading to many residential areas of Canberra, taking fire-fighters by surprise and engulfing parts of the suburbs of Duffy, Rivett, Chapman, Kambah, Higgins, Hawker and Cook. The unique meteorological conditions associated with the approaching fire front caused extreme wind conditions in localised areas of south-western Canberra. These fierce winds uprooted trees, downed power lines, blew in house windows, stripped tiles from roofs, and even embedded pot plants in house roofs ahead of the fire front. Thousands of emergency response personnel and volunteers held Canberra together during the devastating bushfires which claimed four lives, destroyed as many as 530 homes and nearly a million hectares of national parklands and state forest before it was contained. Statistics show that 5% of houses had severe damage caused by wind alone, while another 5% were damaged by both wind and fire. Over a six-hour period at Canberra Hospital, 139 patients (105 with fire-related problems) were treated - one every four minutes. Insured losses from the January 2003 bushfires were estimated to cost $250m, with 2,500 individual claims.

Cyclone - north Queensland - March 2006

Category 5 Cyclone Larry smashed into the far-north Queensland coast, lashing the area with winds of up to 290 km/h. It crossed the coast near Innisfail around daybreak on the morning of Monday 20 March 2006. Gale-force winds uprooted trees, lifted roofs of houses and flattened crops. Fortunately, no lives were lost and no serious injuries were reported. However, between Babinda and Tully, damage to infrastructure and crops was extensive with the total estimated loss upwards of $500m. To a somewhat lesser extent, damage also occurred in areas north to Cairns, south to Cardwell and on the Atherton Tablelands. Larry developed from a low pressure system over the eastern Coral Sea. The low became noticeable on Thursday 16 March and was then closely monitored by the Bureau of Meteorology. It developed into a tropical cyclone during the early hours of Saturday 18 March, and proceeded on a general westerly course towards the Queensland coast. Late in the morning of 18 March, Larry was classified as a severe category 3 cyclone and continued to intensify to a marginal category 5 cyclone as it approached the Queensland coast. Larry was the first severe tropical cyclone to cross near a populated section of the east-coast of Queensland since Rona in 1999 and the effects of the winds on buildings were devastating. Larry caused a significant storm surge, the highest inundation recorded was a substantial 4.9 metres above the expected tide at Bingil Bay. Rainfall associated with Larry resulted in flooding in the Mulgrave, Russell, Tully and Murray Rivers on the north tropical coast and in the Gulf Rivers. The heaviest rainfall, in the Tully River catchment, was over 500 mm recorded at Euramo, near Tully, in the 72 hours to 9.00 am on 22 March.

Floods - Newcastle - June 2007

Over the June long weekend, between Friday 8 and Monday 11 June 2007, the Hunter and Central Coast regions of New South Wales were lashed with severe weather conditions. Torrential downpours and gale-force winds caused flash flooding, and grounded a bulk carrier the Pasha Bulker on Nobbys Beach. Thousands of residents were urged to abandon their homes ahead of a torrent of expected floodwater. The death toll from the three days of wild storms reached nine after a man was swept into a stormwater drain in the Newcastle suburb of Lambton after getting out of his car. At the peak of Friday's wild weather, five members of the same family were swept to their deaths when a section of the Old Pacific Highway collapsed under their vehicle and it was hit by a 'wall of water' at Somersby, near Gosford. Further north, a couple were killed when their vehicle was washed off a flooded bridge at Clarence Town, while a 29-year old man died when a tree fell on his ute at Brunkerville, Lake Macquarie. The State Emergency Service issued an evacuation order for about 5,000 residents of central Maitland, South Maitland, Lorne and Singleton. Sandbagging operations were undertaken at Branxton to protect homes near the river. About 75,000 homes of the Lower Hunter and Central Coast experienced power cuts. The Premier of New South Wales said the damage in Newcastle was worse than that caused by the city's December 1989 earthquake.


Floods - Gippsland - July 2007

Six months previously, Victoria's Gippsland was under siege from bushfires which destroyed everything in their wake and after the inferno, drought gripped the region. In July 2007, residents were dealt another devastating blow as for almost a week Gippsland was awash with the state's worst floods in a decade. Seven rivers burst their banks causing tens of millions of dollars worth of damage to homes, businesses and farms as well as a significant loss of public and private assets. The rapidly rising floodwaters left one man dead and forced dozens of families to be rescued and many communities to be evacuated. More than 48 hours of torrential rain left towns throughout Gippsland struggling to stay above water. Over 1,000 emergency service staff worked to save homes and shops in towns throughout Gippsland where rivers burst over flood plains and roads. Efforts included the evacuation of everyone in Newry, north of Maffra. The Victoria Police air wing winched more than 20 residents to safety, including a woman and her dog.