SE QUEENSLAND AWASH January 13, 2011Posted by wmmbb in Environment.
There has been widespread flooding of both sides of the Australian continent. The weather systems that created floods in the Gascoyne region of WA and in SE Queensland and Northern NSW were probably produced by different systems.
Flooding is having a greater impact on the densely settled areas, including Brisbane. ABC News reports:
Brisbane residents have been told it is not too late to evacuate as a once-in-a-century flood threatens 20,000 homes tonight.
More than 50 suburbs are expected to be flooded when the Brisbane River hits an expected peak of 5.2 metres at about 4:00am on Thursday.
Already thousands of people have been forced to flee their homes after the swollen river burst its banks and reached 4.2 metres on Wednesday.
Premier Anna Bligh is warning despite a slight revision in the expected flood peak, Brisbane residents are going to wake up to a scene of widespread devastation.
“We will wake tomorrow to an image of Brisbane … that will shock many of us and I do say to people that we need to be ready for that,” she said.
“People need to brace themselves.
“I think we are going to see some extraordinary solidarity overnight … and I think that we are going to wake up to a shocking and remarkable challenge.
“But I sense that this is a challenge we are up to and a challenge we will meet.”
Infrastructure was destroyed, 35 suburbs were deluged, and Lord Mayor Campbell Newman warned sewage was seeping into the floodwaters after treatment plants were inundated.
Councillor Newman said the city’s ferry terminals had been “smashed to pieces” while council engineers were forced to demolish the floating RiverWalk around the New Farm cliffs amid fears that it would break away and career downstream.
The Brisbane River was a swirling torrent, with boats, pontoons and other debris being swept towards the sea and muddy water inundating low-lying areas.
The flooding was caused by water surging downstream from the overloaded Wivenhoe Dam meeting a larger than usual high tide.
Authorities warn of a growing risk of disease, including Ross River Fever, hepatitits and gastroenteritis, as the floods linger into the weekend.
The first consideration is of safety of people and the problem often is when the power is cut and the telephone lines are down, it is often difficult to contact them. No doubt mobile phones come into their own, since the towers are usually on high locations. Even when in the more remote areas when the telephone lines were down, provided the power was on, it was still possible for people to send messages via facebook.
For people who live in this part of the world the Pacific Ocean is a constant presence and often an unconscious one. When it comes to weather it seems to the shaping influence. The BBC addressed the question: Why is Queensland Flooded? They suggest:
La Niña is a weather pattern that affects the Pacific Ocean region, and occurs when surface sea temperatures are cooler than normal in the eastern Pacific, and warmer than normal in the western Pacific.
Normally, cold water comes up from the deep sea and pools near the coast of South America. Easterly trade winds drag the cold water from South America across the Pacific towards Australia. The cold water is gradually warmed by the sun as it reaches Australia.
Rain clouds build along the coast of Australia due to the warm moist air, while it tends to stay dry along the Pacific coast of South America.
During La Niña, the cold water that pools near the coast of South America surges across the Pacific and there is a greater build up of warmer water along the eastern coast of Australia. As a result, there is a greater contrast in sea surface temperatures between the east and west Pacific, and a greater contrast in air pressure. The easterly trade winds become stronger due to this contrast, dragging warm, moist air along the Australian coastline, creating larger rain clouds and producing more rainfall.
An El Niño weather event is when warm water pushes towards the central Pacific, the cold water retreats and rain falls in the central Pacific area. Strong El Niño years can cause droughts along the eastern coast of Australia.
The flooding in the Gasgoyne, which I have witnessed in 1969, may have more significance if the cyclone activity on the WA coast is related to wider weather dynamics in the Indian Ocean, and therefore may as a signifier of these conditions be more important for the potential weather impacts of large numbers of people.
Contrary to the consensus of climate science, some believe that global warming and climate change caused by changes in the Earth’s atmosphere as indicated by usually high and increasing levels of greenhouse gases, in particular Carbon Dioxide, is not occurring. Yet there is increasing evidence of extreme weather events, for the example the summer fires in Russia and the Indus floods. It will be interesting to see whether expert opinion regards the Australian floods as part of this wider climate pattern.
I feel very sorry for those who have lost contact with relatives and friends with the number of missing people. I know what it is like not being able to contact people.
As a dog owner, I feel sorry for those who have lost their pets. I was in High Dependency Unit at the hospital, and after not being able to speak for more that four weeks, I was asked about our dogs: Sasha and Dexter.
There are known knowns, even if the frequency of events is uncertain. Typically when we build houses we often do not have regard for natural features such as flood plains, and I suspect the problems are compounded by a disregard for the cumulative consequences of our actions. Gary at Public Opinion points to the responsibility of zoning decisions that have resulted in increasing numbers of people living in natural flood plains.
Scientists are making the connection with Global Warming suggesting an increased frequency of La Nina weather conditions.