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Appendix 7
THE WEATHER OF 1999-2000
Following a waning in mid-1999, La Niña conditions (colder than normal sea surface temperatures in the central and eastern equatorial Pacific Ocean) redeveloped through the second half of the year, peaking early in 2000, weakening again through March and April and remaining weak during May and June.
The La Niña event was marked by very wet conditions over most of Australia during the warmer months, November to April. Extensive areas of Western Australia, apart from the southwest, had their wettest November-April period on record (Figure A7.1). Most remaining areas of the continent north of latitude 30ºS had one of their wettest such periods, except for eastern Queensland, where it was dry in the southeast. Temperatures were also generally well below normal during this period. By contrast, southern parts of South Australia, Victoria, and nearly all of Tasmania had a dry winter and spring. Rainfall continued below normal in southern Victoria and Tasmania through the summer and autumn, continuing the extended drought there that started in October 1996. In contrast, the southwest of the continent - which has had below average rainfall for most of the past 30 years - had a relatively wet winter in 1999.
Figure A7.1. Australian rainfall deciles, which compare the amount of rain over a period with the long-term average for the same period, for the six-month period (November 1999 to April 2000) during which Australia was under the influence of a La Niña event. Extensive areas of very much above average rainfall are evident across most of the continent, with large tracts of Western Australia experiencing their wettest November-April on record, while drought conditions continued in southern Victoria and Tasmania.
The winter of 1999 was generally dry across the southern states, in contrast to the heavy rains which occurred in northeastern New South Wales and southeast Queensland in July. The north of the continent was generally dry between July and September, and wildfires in September and October burnt an unusually large area of the northern half of the Northern Territory, though with little significant damage.
Consistent with a rapidly redeveloping La Niña, as reflected in the Southern Oscillation Index (Figure A7.2), unusually heavy pre-monsoon rains developed over northern and central Australia in October, and more particularly November. Parts of far north Queensland received over 600 mm in November. Persistent rain over the wheat-growing areas of northwestern New South Wales during the November harvesting period caused millions of dollars of damage.
Figure A7.2. The monthly Southern Oscillation Index (SOI) since January 1995, showing the La Niña conditions from October 1999 through May 2000.
In December, tropical cyclone John crossed the Western Australian coast near Whim Creek producing heavy rain of between 200 and 300 mm, or up to 80 percent of the annual average in the affected areas. The remnants of this cyclone moved eastward, producing up to 100 mm rainfalls in normally dry western Queensland. Tropical cyclone John was a very powerful category 5 cyclone, the third such system to affect the northwest in 13 months, but it crossed the coast well distant from any wind measuring equipment.
Southern Victoria and Tasmania continued to experience very dry conditions during spring, raising fears of a severe summer fire season. By late December many irrigators, especially in southeastern Victoria, were running out of water, a legacy of three years of drought. Slow-moving thunderstorms in late December produced up to 100 mm of rain at some places in southeastern South Australia on 25 December, and over parts of central Victoria on 26 and 27 December. This eased the fire danger somewhat, but the rain had little significant impact on vanishing water storages. There was also substantial damage to ripening fruit and unharvested wheat.
La Niña was at its peak between December and March, and rainfall was widespread and heavy. Only the far southeast of the country remained dry. Very heavy and unseasonable rains developed over parts of southern Western Australia on 22-23 January as a surface low-pressure trough interacted with a mid-level disturbance. Some areas of the Western Australian wheatbelt and goldfields regions received in excess of 150 mm, causing major flooding to farmlands. Perth had its second heaviest 24-hour rainfall total on record at 104 mm on 22 January.
In the second and third weeks of February extremely heavy rains drenched extensive areas of central Australia and Queensland, leading to large flows in the ephemeral inland-flowing streams such as the Diamantina River and Cooper Creek. This led to significant flooding in Lake Eyre by April (Figure A7.3), although levels were well below those of the major 1974 flood. Flooding at Winton and Longreach was the worst on record. The rains, due to an unusually well-developed and southward displaced monsoonal trough, were widely 100-200 mm, and in some parts over 400 mm. Heavy rains extended southward into the settled areas of South Australia, into northwestern Victoria, and over western New South Wales, in some cases relieving drought conditions. By contrast, Victoria and Tasmania experienced unusually hot weather in February with Melbourne's average maximum, 30.1ºC, equalling the second highest mean maximum ever for February. Hot weather continued in the first two days of March. Tasmania was plagued by many major bushfires in February, with the loss of thousands of hectares of State forest, but with minimal damage to buildings and property.
Figure A7.3. Satellite image of Lake Eyre, central Australia, as a dry salt lake on 1 January 2000 (left) and with water flooding onto the dry salt pan on 6 April 2000 (right). (Landsat 7 satellite image acquired and processed by ACRES (Australian Centre for Remote Sensing)).
North Queensland had more heavy rain in the last week of February, partly due to tropical cyclone Steve. Falls of 400 to 650 mm in a week led to serious flooding in northeast Queensland, with many properties inundated and some loss of life. Steve then tracked west into the Northern Territory, moving into Western Australia in early March. It then weakened, but still triggered widespread and severe flooding as it moved south through the Gascoyne and Goldfields areas of inland Western Australia, and weakened to a rain depression. Many pastoral stations in the Kimberley, Pilbara and Gascoyne received their average yearly rainfall in just a few days, with some falls over 200 mm in 24 hours. Buildings were flooded and roads cut, leaving communities isolated, in some cases for weeks.
Central Australia received further heavy rain in April, associated with a persistent cloud-band, fed from the northwest by the decaying tropical cyclone Rosita. As much as 300 mm of rain, falling within four days, led to widespread flooding. Up to 200 people in Alice Springs were evacuated and a number of roads closed. Far North Queensland experienced another burst of very heavy rain, with flooding in Cairns and surrounds.
In Victoria, gale force winds on 28-29 April led to dust-storms in the Mallee and Wimmera, described as the worst in over 15 years. Continued below-average rainfall in southern Victoria and Tasmania during April capped a very dry 12 months in these areas, with record low amounts in the area around Hobart.
In late May, a strong low brought very cold air up from Antarctic waters, causing cold and wet conditions in southern Victoria and Tasmania. Heavy snow fell over the Alps, bringing an early start to the snow season, and in some parts of Victoria significant snowfalls occurred to low levels. The catchment areas of southern Victoria, which had been dry for three and a half years, finally received heavy rain in a promising start to the winter season. Very dry conditions in southwestern Australia during May and early June, however, marked a poor start to their winter wet season.
Top of PageThe 1999-2000 tropical cyclone season was very active in the Australian region. There were eleven cyclones, including four which achieved category 5, the most powerful on the severity scale: John, Paul, Norman and Rosita. Another, tropical cyclone Steve, spent two weeks battering northern and western Australia.
Figure A7.4. Tropical cyclone tracks for the 1999-2000 cyclone season. The direction of movement is indicated on each track.
The first cyclone of the season, John, formed on 12 December in Western Australia. It intensified to category 5 on 14 December off the Pilbara coast with winds estimated at up to 290 km/h. John crossed the coast near Whim Creek on 15 December before weakening into a rain bearing depression early on 16 December. The resulting heavy rain, high winds and flooding caused extensive structural damage at many stations in the Pilbara and many mining operations were suspended.
Tropical cyclone Ilsa developed well to the west of Western Australia and initially moved eastwards. Ilsa passed south of Christmas Island on 13 December producing a heavy swell which caused some damage, then tracked southeast towards the Pilbara before weakening and crossing the coast on 17 December.
A developing low was named tropical cyclone Kirrily on 28 January while about 550 km northwest of Exmouth. Following a southwesterly track, Kirrily moved away from the coast without any direct affect on the mainland. The lowest central pressure was estimated at 970 hPa.
Tropical cyclone Steve made a major impact as it tracked over northern and western Australia for a period of almost two weeks. It formed in the Coral Sea, 210 km east of Port Douglas, on 27 February, reached category 2 and moved west across the Queensland coast. Maximum wind gusts were 160 km/h at landfall. Steve then weakened temporarily to a rain depression and caused flooding as it crossed Cape York. A record flood level of 12.4 m was reached at Mareeba on 28 February. Ninety people required evacuation and the railway bridge was washed away. Many buildings in Cairns suffered severe water damage including the Cairns Hospital. Several Cairns and Kuranda buildings lost their roofs, hundreds of trees were uprooted and powerlines were brought down throughout the district, disrupting supplies to more than 40,000 residents. The two highways to the Atherton Tablelands were closed by fallen trees and landslides. Crop damage by floods and winds was severe, with sugar cane damage alone estimated at $20 million. Preliminary storm costs were estimated to include $49 million to restore local government assets and $20 million for state roads and railways. The total damage bill from cyclone Steve for north Queensland may exceed $100 million.
Steve re-formed into a category 1 cyclone near Mornington Island on 29 February, weakened again to a rain depression before continuing westwards and causing widespread flooding in the Katherine, Daly and Victoria regions, and over the Kimberley region of Western Australia on 3 and 4 March, before moving offshore near Broome on 5 March and once again attaining classification as a tropical cyclone. As tropical cyclone Steve it tracked along very close to the northwest coast, finally moving definitively over land south of Carnarvon on 9 March and maintaining a southeasterly track across the Gascoyne, Murchison and Goldfields. On 11 March the low moved offshore across the Western Australian coast to the east of Esperance and over the waters of the Great Australian Bight. The very heavy rainfall associated with the system produced widespread flooding in northern parts of the state including the Gascoyne region. Much of the Kimberley, Pilbara and Gascoyne districts reported cumulative rainfall totals in excess of 100 mm. Higher falls greater than 300 mm were recorded near the 80 Mile Beach. Parts of the western Pilbara and northern Gascoyne received totals that ranged from 200 to 300 mm. Several sites reported highest on record daily rainfall amounts including Mandora 281.3 mm on 6 March and Yaringa, south east of Carnarvon, 175.0 mm on 9 March. Flooding occurred in the Esperance area and several roads and bridges were washed away.
Severe flooding in March 2000 following heavy rains from tropical cyclone Steve cut the South Coast Highway, Western Australia, in a number of places including the Lort River Crossing.
A developing low was named tropical cyclone Leon on 4 March, while located approximately 230 km south of Christmas Island. Following a general southwesterly track on 5 and 6 March, the system developed into severe tropical cyclone Leon with an estimated central pressure of 960 hPa. On 8 March Leon passed to the south of the Cocos (Keeling) Islands without further impact on Australia.
Tropical cyclone Norman was named on 1 March while located approximately 280 km to the north northeast of Karratha. It followed a westerly track across the Indian Ocean and by 3 March the westward moving system had intensified to category 5 with a central pressure estimated at 920 hPa, while about 780 km to the west northwest of Exmouth. On 6 March the cyclone changed direction to a southerly track. Tropical cyclone Norman weakened on 8 March to category 1 and had no direct impact on Western Australia.
A developing tropical low was named tropical cyclone Olga on 17 March while located approximately 570 km to the north of Exmouth. Following a generalised southwest track tropical cyclone Olga intensified to a category 2 cyclone during 18 March with a central pressure of 980 hPa. By 20 March the system had weakened to a tropical low while located about 970 km to the west of Carnarvon. The system had no direct effect on Western Australia.
A tropical low in the northern Coral Sea moved toward the coast, deepened into tropical cyclone Tessi on 2 April and crossed the coast near Bambaroo and Crystal Creek (80 km north of Townsville) early on 3 April as a category 2 system on landfall. Winds unroofed buildings, uprooted trees and downed power lines in the area between Ingham and Ayr. Townsville's waterfront area, The Strand, suffered wave damage with several boats destroyed. Heavy rain caused landslides on Townsville's Castle Hill destroying two homes and requiring the evacuation of another 50. Considerable damage to personal property and to Townsville City infrastructures were reported. Townsville Airport reported a record April wind gust of 130 km/h, a record April daily rainfall total of 271.6 mm and the cyclone was the main contribution to a record April monthly rainfall total of 546.2 mm.
Tropical cyclone Vaughan formed from a tropical low which was first identified near New Caledonia on 29 March. The low tracked northwest through the Coral Sea to become tropical cyclone Vaughan on 4 April. The system rapidly intensified to category 2 and tracked westward toward the north Queensland coast. Vaughan weakened a little on 5 April and was downgraded to a category 1 system before re-intensifying to category 2 early on 6 April. However by late morning on the 6 April the system again rapidly weakened and was downgraded below cyclone strength during the afternoon.
Forming well off the Pilbara coast, tropical cyclone Paul was named on 13 April while located approximately 840 km to the north northwest of Exmouth. Moving in a west southwest direction Paul intensified rapidly to a severe tropical cyclone and reached category 5 status on 15 April. The lowest central pressure was estimated to be have been about 920 hPa the following day. Severe tropical cyclone Paul passed about 200 km to the south of the Cocos (Keeling) Islands on 17 April when the central pressure was estimated to be about 940 hPa. Paul continued to weaken as the system followed a general west southwest track across the Indian Ocean.
Tropical cyclone Rosita was named on 17 April while located approximately 670 km to the north of Port Hedland. The cyclone initially moved in a south southwest direction. Tropical cyclone Rosita intensified rapidly on 19 April to become a severe tropical cyclone category 5 with an estimated central pressure of 930 hPa and wind gusts near the centre of around 290 km/h. On 20 April the severe cyclone crossed the coast about 40 km to the south of Broome. Over land the cyclone began to weaken as it headed into the Great Sandy Desert. Combining with other moisture sources the remnants of tropical cyclone Rosita brought flooding rains to central Australia. A maximum wind gust of 154 km/h, and 163.8 mm of rain for the 24 hours on 20 April were recorded at Broome aerodrome. The high winds unroofed several houses, interrupted power supplies and caused widespread damage to vegetation around the town. Further south in the vicinity of Eco Beach/Cape Villaret and at Yardoogarra Station, 40 km south southwest of Broome, the structural damage was considerably more extensive. Once-green vegetation near the coast was stripped of all leaves by the destructive winds carrying airborne salt and sand.
Top of PageWindy conditions occurred frequently in July over many parts of Australia. In South Australia high winds, driving rain and lightning strikes cut power to more than 17,000 homes in the southern Mount Lofty Ranges, southern Eyre Peninsula, Kangaroo Island, the Riverland and the Mid North on 18 and 19 July. In Queensland strong winds were experienced on the central and southern coast between 25 and 27 July. Cape Moreton recorded a 10 minute wind of 96 km/h and a peak gust to 115 km/h during 26 July. East to southeast swells reaching a significant height of 4.6 m and a peak of 9.5 m on the 26 July exacerbated erosion at Gold Coast beaches. In Tasmania wind gusts of 100 km/h or more were recorded on 9 days.
On 25 August a tornado struck the southern suburbs of Perth and caused significant property damage in East Fremantle. The trail of destruction was about 25 to 50 m wide and 7 km long. Wind gusts associated with the tornado were estimated to have reached 150 km/h.
In September a significant depression and associated frontal system brought gales and thunderstorms to southern states at the beginning of the month. Windy conditions in the Northern Territory fanned several grass fires during the month. In Victoria on 15 and 16 September thunderstorms produced severe gusts in the Central, North Central, Gippsland and Alpine districts. The highest recorded gust was 140 km/h at Falls Creek. Tree and building damage occurred and a house under construction at Geelong collapsed. Large hail occurred with thunderstorms that affected Sydney on 22 September. The storm caused sporadic damage through parts of the Sydney metropolitan area. Sydney Airport recorded a maximum wind gust of 87 km/h. Impacts included hail damaged roofs, fallen trees and lightning strikes.
Severe thunderstorms accompanied by hail and damaging winds occurred in several states during October. In Queensland on 4 October, severe thunderstorms brought widespread torrential rain to the southeast with flash flooding in Ipswich, Brisbane's western suburbs and the Gold Coast. Power lines were downed in Ipswich and more than 5,000 homes lost power. Strong to gale force squally winds affected a large area of the southern half of Western Australia on 7 and 8 October as a very active cold front associated with an intense low crossed the west coast. On 7 October Rottnest Island reported a gust to 113 km/h, Cape Naturaliste 106 km/h and Swanbourne 100 km/h. On 23 October severe thunderstorms with extensive hail destroyed crops in fruit growing areas from Texas to Stanthorpe in Queensland. Damage estimates range from $10 million to $30 million. Hail also caused crop damage in New South Wales, Victoria and South Australia.
Thunderstorms occurred in all states in November. In Queensland on 16 November, hail destroyed 6,000 hectares of cotton worth about $18 million on the Darling Downs and at Cecil Plains $2 million worth of crops were destroyed due to golf ball-size hail. In Western Australia thunderstorms developed about the Southwest Land Division between 1 and 4 November. There were instances of significant hail damage to crops particularly in northern agricultural districts in the Coorow Kalannie area. In Western Australia on 27 November isolated severe storms developed in the Murchison district. Mount Magnet recorded wind gusts to 94 km/h and 10.6 mm of rain fell in 10 minutes. Minor flooding occurred in the town and several houses and businesses were affected by the encroaching waters. The strong winds blew down numerous fences, lifted roof sheeting from several buildings and pushed trees onto overhead power lines. In Tasmania storm force winds of 93 km/h were recorded at Maatsuyker Island and five people died in a boating mishap off Bruny Island on 13 November.
Severe thunderstorms affected most states during December and several locations recorded rainfall records during the month. In Queensland severe thunderstorms affected areas between Warwick on the Darling Downs and eastward through southern Brisbane to the Gold Coast area and around the Lowood area on 10 December. There was hail and wind damage to eleven buildings in Boonah including $500,000 damage to a school. Many trees were blown over and estimates of wind to 100 km/h were reported. Extensive damage was caused to power lines with power loss to more than 35,000 homes. On 8 December extensive thunderstorms were reported across South Australia. The most severe damage was reported in and around Snowtown, in the Lower North district with hailstones up to 4.5 cm in diameter, heavy rain of 40 mm in one hour and strong winds to 122 km/h recorded at Snowtown. The storm caused considerable damage to crops, trees, powerlines and buildings along a corridor 8 to 10 km wide.
Thunderstorms accompanied by hail were reported in most states during January. Hail and strong winds occurred on 1 January in areas west of Gympie to Tin Can Bay in Queensland. Marble to golf ball-size hail ruined squash, macadamia and other horticultural plantings. In New South Wales on 1 January, hail of 4 cm in diameter was reported at Armidale and 50 homes and hundreds of cars were damaged and plants and trees were shredded. On 19 January at Gloucester, 2 cm hail and severe wind gusts to 130 km/h were reported with extensive damage over a one kilometre wide path. In the Northern Territory on 15 January, a wind gust of 126 km/h caused damage at Yulara Airport. Power supplies and security systems at the airport were also damaged by lightning. On 17 January an active thunderstorm squall line produced widespread power blackouts and damaged electrical equipment in Darwin suburbs and adjacent rural areas. During the storm, 1438 lightning strikes were recorded in two hours. On 31 January a brief afternoon thunderstorm damaged trees and caravan annexes south of Darwin. Wind gusts estimated to be between 100 and 150 km/h, associated with a sustained wet microburst of about 30 minutes duration, produced a damage trail about 500 m long and 20-100 m wide along the Stuart Highway, with localised flash flooding in an adjacent caravan park.
In Victoria on 25 February, storms in and around Melbourne produced heavy rain leading to flash flooding. At Werribee 40 mm was recorded in 30 minutes and a nursing home had to be evacuated due to the flooding. A water spout was observed near Mt Martha on the Mornington Peninsula. Many thunderstorms were reported on 21 February in South Australia. Lightning strikes caused power blackouts and heavy showers caused localised flooding at Eudunda. Minor roads in the Adelaide Hills received substantial damage, a bridge collapsed and roads were washed away. Further rain and thunderstorms in the Riverland added to the already flooded vineyards and reduced the grape harvest by up to 20 per cent. At Moonta Bay, a fishing boat moored next to the jetty sank after being struck by lightning. During the afternoon of 26 February heavy showers at Booleroo Centre, northeast of Port Pirie in the Mid-North, caused localised flooding.
In New South Wales on 5 March at Katoomba, 2 cm hail and 37 mm of rain fell in 30 minutes. At Gloucester 22 mm of rain fell in 10 minutes and flash flooding was reported at Nundle, which experienced 100 mm of rain in 60 minutes, severely damaging sheep yards. On 19 March at Baulkham Hills, flash flooding was reported when 42.5 mm of rain fell in 60 minutes. In Tasmania, gales on 18 March disrupted power supplies across much of the State. On the same day four people were rescued near Cockle Creek after their boat capsized. Wind gusts exceeding 90 km/h were reported on 10 days at Mt Wellington. In Victoria, a gusty southwest change on 22 March produced severe gusts to 90 km/h and raised dust in the Wimmera district, south of Horsham.
In New South Wales, on 1 April at Denman, wind gusts to 92 km/h were recorded, trees were blown down and some roofing iron removed. On 21 April, 4 cm hail was reported at Ulladulla. In South Australia on 9 April thunderstorms developed on and west of the Flinders and Mount Lofty Ranges during the afternoon. Heavy showers caused flash flooding in the Lower North, Mount Lofty Ranges and the Adelaide Plains. Houses were flooded and roads closed in the Lower North townships of Gladstone, Crystal Brook and Port Pirie. Gulnare, also in the Lower North, received 63 mm of rain in 24 hours, breaking the daily rainfall record set in 1905. Lightning struck two trees in the eastern suburbs of Adelaide causing minor scrub fires. Further thunderstorms on 11 April, in the north of South Australia, caused more flooding and road closures. A four-wheel drive vehicle was swept away by flood waters at Farina, south of Marree, when a creek burst its banks. In the Northern Territory on 12 April, a long-lived thunderstorm squall line moved across the northwestern Top End and produced winds gusts of 94 km/h at Lee Point, 10 km north of Darwin, and 83 km/h at Charles Point, 25 km west of Darwin. A fisheries research vessel was swamped by waves during the storm and sank while being loaded on Melville Island. In Tasmania early on 16 April, thunderstorms caused damage to houses, trees and power supplies in the north of the State, particularly around Ulverstone where one roof was carried about 500 m. In Victoria on 20 April, a waterspout was sighted off Coal Point (near Inverloch).
In Queensland, the combined effect of a high pressure system over the Tasman Sea and a low off Queensland's Capricornia Coast between 1 and 3 May brought strong to gale force winds and very rough seas to the area. The winds caused powerline damage and felled trees. Easterly swells averaging 5 m were reported off the south coast. In Victoria, on 13 May severe gusts to around 95 km/h occurred in the eastern suburbs of Melbourne causing minor damage. From 27 to 29 May, severe gusts and squalls were recorded, with the highest being 132 km/h at Mt Buller and 124 km/h at Fawkner Beacon. In South Australia, Adelaide Airport recorded a gust of 94 km/h on 26 May. In Tasmania, blackouts due to lightning strikes and strong winds were experienced in the north of the state on 26 May. A line of showers and thunderstorms associated with this cold front crossed southern South Australia producing wind gusts to 90 km/h during the morning of 26 May. A cold squally southwest airstream followed the front, bringing widespread showers with isolated small hail across agricultural districts.
June was marked by several episodes of gales and winter thunderstorms over southern Australia with accompanying hail and reputed tornadoes. On 21 June, storms caused wind damage across the Southwest Slopes and Southern Tablelands of New South Wales and across the Northeast of Victoria. A tornado, with a narrow damage path, was observed at Wallan in the Central district. On 22 June, tornadoes caused damage to houses and trees at Rochester and Kyabram. A family at Rochester escaped serious injury when the tornado passed over their house. In South Australia a cold southerly change on 28 June, brought heavy hail showers to much of the southern agricultural districts. In the Mount Lofty Ranges a hail storm caused five separate motor vehicle accidents involving 20 cars and one semi-trailer. In Western Australia on 10 June, localities near the lower west and south coast experienced strong to gale force winds during the passage of an active cold front. On 30 June, storms developed in the vicinity of Perth and a tornado damaged several properties in the East Fremantle area. The short duration tornado produced a damage trail about 30 metres wide and 800 metres long, with wind speeds estimated to have reached 150 km/h. In Tasmania on 1 June, strong winds blew down trees over power lines causing blackouts in several areas around the State.
Top of PageA series of slow-moving cold fronts in July produced heavy rainfall near the coast in the lower west and south of the country between 2 and 4 July. Several localities in Western Australia reported daily totals in excess of 75 mm, including 92 mm at both Bunbury and Dardanup on 4 July. Flooding developed in the Busselton area and a number of residences were evacuated as waters from the Vasse River and other waterways encroached on the town. Busselton Aerodrome reported 123 mm of rain in the 48 hours to 9am on 4 July. In South Australia a primary school at Rapid Bay on the Fleurieu Peninsula was evacuated when an intense downpour caused flash flooding of small creeks in the area. At Second Valley, about 8 km east of Rapid Bay, mud slides threatened a motel and three houses as rising water levels burst a river levee. At Yankalilla, a restaurant and motel were threatened with flooding when the local river rose rapidly. A deep low pressure system to the west of Tasmania bought a series of rain periods which caused some flash flooding and minor flooding in the Meander River. In New South Wales, moderate flooding occurred in the Hastings, Manning and Lower Hunter Rivers, with only minor flooding in the Clarence and Nambucca Rivers.
In August and September heavy rainfall resulted in a period of minor flooding in the Ovens and King Rivers, the Avoca and the Loddon Rivers in Victoria. In September the passage of several cold fronts produced snowfalls in far southwest Western Australia. On 3 September a light covering was observed in Bluff Knoll. A blanket of snow covered the upper reaches of Stirling Range on 15 September.
During October, the passage of an upper trough led to moderate flooding in the lower Macintyre River in Queensland which continued into November. Further rainfall caused only minor flooding in rivers in southern central Queensland, including the Condamine-Balonne, Paroo Rivers and Thomson, Barcoo Rivers and Cooper Creek. Floodwaters from these events led to minor flooding downstream as these floodwaters moved through the river system into New South Wales. There was further minor flooding in New South Wales rivers during October and November including the Lachlan, Castlereagh, Gwydir, Georges and Moruya Rivers, with some moderate flooding in the Nepean-Hawkesbury system.
In December, severe tropical cyclones John and Ilsa led to widespread major flooding in the coastal streams of the Pilbara region of Western Australia. Significant disruption to railway infrastructure of mining companies and road transport was experienced. The town of Newman was also badly affected by flash flooding during the month. In Victoria heavy rainfall led to minor flooding in the Avoca and Loddon Rivers.
Flooding continued in a number of western Queensland rivers at the beginning of January as a result of rain at the end of December. The most significant flooding occurred on the Thomson, Barcoo Rivers and Cooper Creek on 1 January where the main floodwaters in the Cooper Creek system were downstream of Windorah. However major flooding was still occurring in Cooper Creek at Windorah and moderate flooding in the Thomson River at Jundah. Flood warnings remained current until 5 January. In Tasmania, heavy rainfall in the northeast on 4 January led to flooding for several days, mainly in rural areas. Major flooding was reported at Cullenswood on the Break O'Day River, while moderate flooding was reported on the South Esk and St Pauls rivers. Land owners were forced to move stock, but no significant losses were reported . Several roads were cut and some bridges damaged. One wooden bridge was destroyed near Scamander on the East Coast. On 22 and 23 January heavy rainfalls over areas of Western Australia resulted in many locations reporting record January monthly rainfall totals. On 22 January, Colorado (106.4 mm) and Lake Carmody (112.4 mm), recorded their highest ever daily rainfall totals.
Periods of heavy rainfall during February resulted in major flooding in many areas of Queensland with over 230 flood warnings being issued. Heavy rainfalls brought three distinct wet periods during the month: early to the mid-month, floods occurred in coastal catchments from Mackay to Ingham; mid-month the monsoonal trough resulted in heavy rainfall over far western catchments; and late in the month tropical cyclone Steve caused flooding in coastal rivers and streams from Ingham to Cooktown. On 17 February major flooding on the Haughton River resulted in the inundation of the township of Giru. Later in the month tropical cyclone Steve caused the Barron River at Mareeba to reach its highest flood since records began in 1921. The township of Winton was subjected to some of its most severe flooding on record during the middle of the month. Heavy rainfall on 28 February, that extended from the northwest through to the Goldfields and eastern parts of the Southwest Land Division were triggered by a tropical low over the Pilbara. Esperance recorded a notable 70 mm of rain in the 9 hours to 9am on 28 February. The unseasonable rainfall produced localised flooding around the town and interrupted electricity supplies. In the Northern Territory the Todd River flowed through Alice Springs during February reaching a peak of 2.18 m on 14 February. The Hugh, Finke and Palmer Rivers all flooded and reached record heights at the Stuart Highway. On 12 and 13 February, the Hugh River reached 6.7 m (3.5 m over the bridge), the Finke River reached 9.64 m (6.3 m over the bridge) and the Palmer reached 11 m (1 m over the bridge) following record rains in the West Macdonnells. The Hugh river flooded the Owen Springs homestead to about 1 m depth and at Orange Creek homestead flooding was about 2 m deep. On 16 February, monsoonal rainfall in the Darwin region caused flash flooding in the suburbs and rural areas and arterial roads were cut.
As noted earlier, tropical cyclone Steve caused extensive disruption to communities across the north and west of Australia as it moved across the Queensland coast near Cairns in late February then across the Northern Territory, down the Western Australia coast and finally moving southeastwards through the Great Australian Bight in mid-March. Several sites reported highest on record daily rainfall amounts, including Mandora at 281.3 mm on 6 March and Yaringa, south east of Carnarvon at 175.0 mm on 9 March. On 1 March the Hodgson River at Hodgson River Station rose quickly to 12.35 m and threatened the homestead following falls of nearly 200 mm of rain in the catchment. The Katherine River at Katherine rose quickly from 4 m on 1 March to 8.9 m on 2 March peaking at 17.45 m on the 3 March. On 2 and 3 March the Cullen River cut the highway south of Pine Creek. Also on 2 March, the Waterhouse River rose after heavy rainfall and entered the Beswick community causing some relocations to higher ground. Further downstream the Djilkminggan community of 300 people was evacuated to Mataranka.
At the beginning of April, tropical cyclone Tessi crossed the Queensland north tropical coast followed a week later by tropical cyclone Vaughan. Only three river basins were affected by the resultant rain. Widespread heavy rainfall on 3 April, following ex-tropical cyclone Tessi, caused rapid river rises throughout the Haughton River catchment. River levels downstream at Giru reached 2.85 m on 4 April, the highest since the start of records in 1978, causing major flooding. Ex-tropical cyclone Vaughan resulted in heavy rain in the Tully River catchment on 7 and 8 April. The Tully River at Euramo peaked just above the level of the Bruce Highway on 9 April causing moderate flooding. Widespread rains in the western parts of the Alice Springs district in the Northern Territory caused flooding mid-month, with the Todd River peaking at 3.2 m on 21 April at Anzac Oval, 2.0 m above flood level. About 100 people from low lying areas were evacuated to higher ground and the Stuart Highway was closed at several places including Heavitree Gap in the McDonnell ranges.
In the Paroo River catchment in Queensland, rainfall totals up to 130 mm were recorded, from 2 to 6 May which resulted in major flooding throughout the catchment with the main flood waters reaching Hungerford about 11 May. Moderate flooding resulted in the Bulloo River during the same time as the floods in the Paroo. The main flood waters reached Thargomindah on 18 May causing minor flooding. During the last week of May a major trough crossed eastern Australia with strong cyclogenesis near Tasmania. This produced a spell of very cold and windy weather in South Australia and eastern States with snow to very low levels. In Victoria from 27 to 29 May the cold outbreak produced snow falls in southern and mountain districts. Near Marysville a person was killed by a falling snow covered tree. In central Melbourne, light snow falls were observed. In Tasmania the spell of cold weather between 27 and 30 May saw snowfall to many elevated areas. The Murchison and Lyell highways were both cut due to snow at various times during the period. Twenty car accidents were reported, mostly in southern Tasmania. In South Australia, snow was reported on the higher parts of the Mount Lofty and southern Flinders Ranges on 27 May.
In South Australia on 20 June, gale force winds coupled with high tides caused minor flooding to low lying areas in some north western suburbs of Adelaide and caused minor damage to property on Eyre Peninsula. Snow was reported to have fallen at Hallett, in the Lower North on 28 June.
Top of PageIn the Northern Territory on 1 July over 200 grass and scrub fires around Darwin and adjacent rural areas and 18 fires in Katherine were reported following fireworks celebrations. No significant damage was reported. From 22 to 24 July bushfires destroyed large areas of pasture at Edith Farm near Katherine, at Point Stuart east of Darwin and at Mainaru in the Arnhem district.
Dry and windy conditions over the Top End of the Northern Territory caused a number of bushfires in August. From 3 to 5 August a large fire burnt about 200 km2 of pasture on Manbulloo, Scott Creek and Dry River pastoral stations southwest of Katherine. A large fire also affected the Larrimah and Gorrie station area south of Katherine on 6 August. On 15 August a fire swept through Humpty Doo, McMinns Lagoon and the Howard Springs area, 40 km southeast of Darwin, threatening houses and destroying irrigation equipment. Bushfires in the Acacia Hills area, about 50 km southeast of Darwin, on 16 and 18 August affected about 20 properties over an area of about 800 hectares. Houses were threatened and mango plantations, baling hay, irrigation equipment and pasture were destroyed.
Windy conditions in the Northern Territory fanned several grass fires during September. Strong and gusty westerly winds produced extreme fire danger in the western Alice Springs region on 15 September. Three very large fires of over 1000 km2 each burnt scrub and grassland in the northern Tanami desert, the northern Barkly and the southern Gulf Country during the last three weeks of the month. No damage was reported apart from significant loss of pasture. In the Darwin region, 118 grassfires broke out during September. The largest fires, in the McMinns Lagoon and Humpty Doo rural areas on 27 and 28 September, burnt over 100 hectares, threatened houses and caused thousands of dollars of damage to vehicles, crops and equipment.
Significant areas of the northern half of Western Australia and parts of the Northern Territory, were affected by bushfires during September and October 1999. Lightning caused around 10 fires in pastoral areas between Katherine and Newcastle Waters during the first week of October. Large areas of grassland were burnt in the northern Barkly, western Gulf Country and southern Katherine regions. Significant loss of pasture and fencing was reported from the affected pastoral properties. Wildfires burnt an unusually large area of the northern half of the Northern Territory. There was little significant damage, considering the area burnt, apart from loss of pasture and some fencing. In Western Australia on 30 and 31 December, lightning sparked a bushfire that burnt about 45,000 hectares in the Beekeepers Nature Reserve near Leeman.
In Tasmania on 12 January, a scrub fire destroyed five houses in Gormanston and Linda. A fire burnt out 300 hectares of forest east of George Town on 3 January. In South Australia, lightning started a bushfire in the Senior area of the Upper Southeast district on 10 January, where a total of 800 hectares was burnt out. A lightning strike started a scrub fire in the Hambridge Conservation Park on Eyre Peninsula on 11 January. Temperatures in the mid to high 30s and hot northerly winds caused the fire to spread, eventually destroying two thirds of the 40,000 hectare park by 17 January.
In Tasmania, many major bushfires were reported during February, affecting 2,000 hectares of native forest near Glen Huon on 5 and 6 February, 200 hectares of bush near Burnie on 13 February, 800 hectares of State forest near Lorinna from 15 to 17 February, and 1,600 hectares of bush near Gowrie Park on 20 February, with 200 hectares of bush and houses threatened at Ravenswood on 20 February.
On 2 March, bushfires occurred at various locations in the north, east and south of Tasmania. On 29 April, bushfires occurred near Mayfield in the north of Tasmania and near Neika and Glenorchy in the south, but no serious damage was reported.
Dry and gusty south east winds resulted in a period of very high fire danger over the Top End of the Northern Territory during the last four days of May. A large wildfire on 27 and 28 May burnt out 50 km2 of bushland in the Marrakai /Corroboree area, about 90 km east southeast of Darwin. The fire threatened several houses in a subdivision, but no major property damage occurred.
A number of bushfires were reported across the Northern Territory in the first half of June, most of them deliberately lit, threatening homes near Noonamah, Humpty Doo, Elizabeth Valley, Lake Bennett, Darwin River and other areas. On 7 June, a helicopter and a 20 kilometre fire break were required to protect the town of Batchelor from a bushfire which burnt about 140 km2 before being contained. On 13 June, a fire burnt 60 hectares of bushland in the Darwin suburb of Ludmilla, requiring backburning to save over 50 homes and causing zero visibility along nearby roads.
Top of PageDespite overall high mean temperatures for 1999 (Figure A7.5), November and December were both exceptionally cool months over Australia, with continental average maximum temperatures being the coldest in the high-quality monthly temperature records available since 1950.
Figure A7.5. Mean temperature anomalies for 1999 showing mean temperatures as slightly above the long-term average over most of Australia.
Maximum temperature anomalies were greatest over eastern parts of Western Australia and southwest Queensland, with December maximum temperatures over southwest Queensland being 4 to 6 degrees below the long-term average, at least in part due to frequent cloud and rain.
Victoria and Tasmania experienced unusually hot weather in February, with Melbourne's average maximum of 30.1ºC, equalling the second highest mean maximum ever for February. Hot weather continued in the first two days of March.
During the last week of May a major trough crossed eastern Australia with strong cyclogenesis near Tasmania bringing very cold air up from Antarctic waters and producing a spell of very cold and windy weather in South Australia and eastern States with snow to very low levels.
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