The main reason why the 2010-2011 floods happened in Australia is, 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. Water collected along the escarpment at the top of the range and 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 largely why Brisbane and Ipswich flooded. An inquiry into the release of water from Wivenhoe is underway.
Many of the river systems further west which were affected by the flooding which had occurred regularly through December and January feed into the Darling River, which then leads to the Murray River. The Darling River catchment, and catchments east of this, received more rainfall than its capacity can take, and as the floodwaters moved downstream, communities in New South Wales, western Victoria and South Australia were affected as well.
The 2010-2011 floods in Australia were caused by heavy rainfall during the La Niña weather phenomenon, which brings increased rainfall to the region. The combination of above-average rainfall, saturated soils, and overflowing rivers contributed to the widespread flooding in various parts of Australia.
Thirty five people died in the floods in Australia in January 2011.
Nothing. Heavy floods do not occur in plants.
As of now, authorities are still assessing the extent of the damage and the number of missing persons in the Australian floods. Information regarding missing individuals is continuously updated, so it is important to follow official announcements for the most accurate data.
Meteorologists classify floods based on their cause, such as heavy rainfall, snowmelt, or dam failure. They also categorize floods by their severity, which can range from minor to major to catastrophic. Additionally, floods can be classified by the area they affect, such as urban flooding or river flooding.
Flooding is most common in low-lying areas and regions with heavy rainfall, such as river valleys, coastal areas, and places with poor drainage systems. Additionally, areas prone to tropical storms and hurricanes are particularly susceptible to flooding.
December 2010
the floods started on 12-Jan-2011 01:59
13th of march 2011
The floods in Rains Season 2010-2011
In the 2011 floods in Queensland Australia only 20 died. As it is a vast country with fewer population.
The Floods that happen suddenly are called Flash Floods.
because there was a tropical cyclone and the rain was heavy daah
Queensland
July 25 2010
a lot
Holmfirth Floods happened in 1821.
Flash floods