How long did the Queensland floods last?

Answer 1

The 2010-2011 floods in Queensland started in central Queensland around 10 December.

As of January 11, the floods had still not finished. Many towns such as St George remain under threat while Rockhampton, for example, was underwater until at least mid-January.

Meanwhile, capital city of Brisbane faced massive flooding for several weeks.

Answer 2

Queensland is a huge state. Floods frequently occur in the north during the monsoon season, while the west, southwest and central regions experience drought.

In May 2009, Queensland experienced widespread flooding in the gulf country, which is in the north and northwest of the state. These floodwaters travelled all the way into South Australia to fill Lake Eyre, an event which occurs about every ten years.

Also in May 2009, the city of Brisbane officially cast off its "drought" status for the first time in years, as the city and surrounding areas of the Gold and Sunshine Coasts and Redlands, have receievd a third of their annual rainfall in one day. This resulted in flash flooding in many areas of Brisbane, possibly made worse by extensive tunnelling and roadworks in the city.

In early March 2010, there were floods in Gympie as well as southwestern Queensland, such as Roma, Charleville, St George and Thargomindah. The flooding in the southwest occurred at the headwaters of the Darling River, bringing vital water into the parched Murray-Darling system.

More recently again (December 2010-January2011), there were massive floods right across the state of Queensland. These floods affected a much wider area, hitting cities such as Rockhampton and Emerald particularly hard, and causing mass evacuations across the state. Towns affected have included St George, Mundubbera, Dalby, Theodore, Chinchilla, Gayndah, Condamine and Warwick, just to name a few. A cyclone system which crossed the coast south of Cairns brought flooding to that city at Christmas.

What has been described as an inland tsunami hit Toowoomba, at the top of the Great Dividing Range, sending a mass of water down the range to swamp the towns at the base. Helidon and Grantham were particularly hard hit. The water then made its way into Wivenhoe Dam, contributing to the dam reaching a capacity in excess of 190%. This meant a lot of water had to be released into the Brisbane River to prevent overflow of the dam. This in turn swamped Ipswich and Brisbane, leading to devastating floods in both those cities.

Answer 3

The floods affecting Queensland this summer (2010-2011) began in parts of Queensland as early as December 10. With many properties already under threat, conditions worsened considerably when a widespread cyclone system hit northern Queensland on Christmas Day, dumping huge amounts of rainfall right across the state.

The floods really began to be felt just after Christmas as major centres like Rockhampton and Bundaberg were inundated. The floods then hit many other towns, until finally on 11 January, the Brisbane River actually began to break its banks

Answer 4

The 2010-2011 floods in Queensland started in central Queensland around 10 December. Floods are not necessarily a sudden event, and properties were already under serious threat back then.

As of January 7, the floods have still not finished. Many towns such as St George remain under threat while Rockhampton, for example, is expected to be underwater until at least mid-January.

Answer 5

The main reason why the 2010-2011 floods happened in Queensland was, quite simply, because of the unusual amount of rain.

Australia spends many years in drought, often caused by the El Niño effect. When an El Niño occurs, changes in sea surface temperatures cause a shift in air pressure which, in turn, can result in climatic anomalies, such as severe droughts in Australia. These years are punctuated by years of normal rainfall, but occasionally, Australia gets the opposite to an El Niño, which is La Niña. This means that weather conditions, etc, are in reverse to those seen during El Niño, and Australia experiences far more rain than usual.

Australia had been coming out of an El Niño for some time, which means that many parts of Australia had seen gradually increasing rainfall. The rainfall recorded in September 2010 made it Australia's wettest month overall in 110 years. Queensland already experienced flooding in early 2009 (at the same time that southern Australia had the terrible Black Saturday bushfires), and higher than normal rainfall in 2010, increasing towards the end of the year. By then, the ground was simply too saturated to hold any more water. Add to that the effects of the cyclone which crossed the north Queensland coast at Christmas time, bringing excessive rainfall to north and central Queensland, and the ground was waterlogged. (A similar pattern led to the Brisbane floods of 1974.)

Radar images show how large the cyclone system was, even though it was only a category one cyclone, the lowest grade. Low wind speeds do not necessarily mean low rainfall, and in this case the cyclone brought large amounts of rainfall right along the coast. Some of the water runoff from the north flowed down through the inland river system; some of the rainfall fell into the catchment areas of coastal rivers further south. The rivers broke their banks more easily, and there was nowhere for the excess water to go.

Rain continued to fall heavily throughout early January. On 10 January 2011, Toowoomba, a city which sits at an elevation of 700m at the top of the Great Dividing Range, received 150 mm of rain within a 40 minute period. The ground could not hold any more water, and the waters from the escarpment at the top of the range rushed in a torrent towards the city. Stormwater drains and creeks coming through the two natural valleys in the city were already overflowing, unable to cope with the sudden torrent of rain. The water from the top of the range then met huge large amounts of water from East Creek and West Creek, meeting at Gowrie Creek. This impact created the wall of water, a 7m high inland "tsunami", that went through the city and down the range. This wall of water rushed through Lockyer Valley to the catchment areas of the main dam that protects the city of Brisbane from flooding, sending its capacity to 190%. The gates had to be opened, sending the equivalent of two Sydney Harbour's worth of water into the Brisbane River each day. This is why Brisbane and Ipswich flooded. An inquiry is currently underway investigating the issue of water releases from the dam, and whether actions should have been different.

Answer 6

There have been many major floods in Queensland. This answer pertains to the devastating floods of summer 2010-2011.

The first floods were in Cairns in the far north; the floodwaters then extended down to Rockhampton, completely swamping the city, also affecting Emerald to the west. Other centres affected include Bundaberg, Maryborough, St George, Mundubbera, Dalby, Theodore, Chinchilla, Gayndah, Condamine, Helidon, Grantham, Murphy's Creek, Gatton, Laidley, Toowoomba and Warwick, just to name a few.

From 11 January, major flooding began in the large city of Ipswich, and Brisbane the capital of Queensland. This flooding affected around 20,000 people in dozens of suburbs along the Brisbane River and the Bremer River in Ipswich.