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Floods in Australia Caused By The La Nina Phenomena
The Great Barrier Reef and The Awesome Powers of Mother Nature:
The La Nina Phenomena and How it Affects our Weather
Queensland Australia has suffered its wettest ever December, according to the Australian Bureau of Meteorology, during what it describes as a "very strong" La Nina event in the Pacific Ocean.
In June 2010 the bureau stated that La Nina was likely to have an effect on Australia by the end of that year. Floods have devastated the landscape of the state of Queensland, Australia, but they also present a high risk to the Great Barrier Reef.
Massive floods have shut down the centre of the Australian city of Brisbane as rescuers search for 67 missing people. The biggest floods in the region in a century have so far killed 16 people since starting their march across the state of Queensland last month.
Australian Floods and The La Nina Phenomena
The flood surge is expected to peak in Brisbane, a city of 2m people, and last for days. More than 50 suburbs and 2,100 roads are under water after the Brisbane River bursts its banks and swamped the city centre. Brisbane, the cosmopolitan state capital and economic hub, is the latest and biggest victim of floods caused by months of rains that have turned three-quarters of Queensland into a disaster zone.
Rescue crews took advantage of some rare sunshine to look for 67 people still missing from flash floods that tore through townships west of the city this week.
La Nina - El Nino phenomena
Most of the time the La Nina and the El Nino phenomena occur as a result of some kind of interaction that occurs between the atmosphere in the tropic Pacific and the surface of the ocean waters.
This happens when changes in the atmosphere cause some kind of feedback change in the ocean currents and in the temperatures of the waters. When this ocean system becomes warm, we call it El Nino. When the ocean system becomes cold, it is usually referred to as the La Nina phenomenon.
In short, both weather names refer to conditions that characterize two extreme phases of a natural climate cycle that can be described as the El Nino or Southern Oscillation. Both the La Nina and El Nino terms refer to the large-scale shifts and changes that occur in the sea surface temperature of the eastern tropical Pacific Ocean.
Mass Evacuation in Australia After Floods
El Nino and the La Nina phenomena
Most of the time, sea surface temperature readings done of South America's west coast will range anywhere between 60 and 70 degrees Fahrenheit. The so-called warm pool located in the western and near central Pacific will often exceed the 80s. However, the sea surface temperatures located along the equator will usually fall by as much as seven degrees..
But what specifically is responsible for the phenomenon of La Nina? The phenomenon of La Nina is generally caused by a cooler than average sea surface in the tropical area of the Pacific. This causes the cold water to move up to the surface of the waters when the atmosphere is moving in a generally eastward direction, as well as the oceanic waves which are also moving east. In general, the El Nino and the La Nina phenomena are built through a series of very complex movements and events which scientists still do not have a clear explanation for.
Queensland Australia January 2011
Brisbane, Australia, Weather History
Brisbane experienced major flooding in 1893 and 1974 as the Brisbane River broke its bank and inundated low lying areas.
Towns including St George and Theodore had dealt with major flooding earlier in 2010. The floods were a result of heavy rainfall caused by Tropical Cyclone Tasha that combined with a trough during the peak of a La Nina event.
The 2010 La Nina weather pattern, which brings wetter conditions to eastern Australia, was the strongest since 1973.
This La Nina event caused a prolonged event of heavy rainfall over Queensland river catchments.
Record or near to record sea surface temperatures were recorded off the Queensland coast in late 2010.
December 2010 was Queensland's wettest on record, with record high rainfall totals set in 107 locations for the month.
The state average rainfall level of 209.45 millimetres (8.25 in) exceeded the previous record of 200.
1 millimetres (7.88 in) set in 1975.
Brisbane Australia Weather History
2010 was also recorded as the state's wettest spring since 1900 and the Australian continent's third wettest year.
Kevin Trenberth thought climate change as a contributing factor in the unusually high precipitation rates. He attributed a half degree Celsius rise in ocean temperatures around Australia to global warming which produces extra water vapour and intensifies the monsoon.
Other scientists say that it is too early to draw such a conclusion. Assertions were also made that mismanagement of the Wivenhoe Dam might be a contributor to the some flooding in the lower Brisbane valley although this is disputed by engineers.
Floods in Australia
Power Restored to Homes After Flooding
Power has been restored to 170,000 homes in Brisbane. The power company Energex said 66,000 homes across southeast Queensland remained without electricity. As the country's wild summer weather continued, police evacuated communities in neighbouring New South Wales State overnight as flooding threatened the border towns of Boggabilla and Toomelah.
Torrential rain in Victoria State also led to evacuations in Halls Gap and Glenorchy, with a flood peak expected on Friday morning. The town of Beaufort was also under threat with a nearby lake threatening to burst banks, police said.
Similar extreme weather has brought devastation to other parts of the world in recent days with nearly 450 people killed in floods and landslides in Brazil and 23 dead in Sri Lanka.
Flood Waters Recede Leaving Foul Smelling Mud
Foul Smelling Mud as the Flood Waters Recede
In the centre of Brisbane, a drop in the swollen Brisbane River left foul-smelling mud covering areas beside the city's cultural centre and Wheel of Brisbane tourist site.
Bligh called for insurers to show compassion and flexibility, amid reports some residents faced difficulty with payouts against a damage bill expected to top 5 billion, with 1 billion of that to be underwritten by insurers.
"It's not in the interests of anyone in our community, including those companies, to stall or delay recovery," said Bligh, whose disaster handling has won wide praise, reviving ruling Labour’s flagging hopes of re-election in the state.
Bligh said many Queenslanders had taken out insurance believing they were covered for floods and were now discovering they were not protected.
The flooding which started before Christmas continued in other areas of Queensland, with the 6,000 residents of Goondiwindi southwest of Brisbane facing a record flood.
Aerial views of Brisbane showed a sea of brown with rooftops poking out, but the water was receding.
Boats have had to be used in many areas to reach houses, with sofas and fridges floating in filthy water, and residents with no idea when they can return.
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© 2011 Christine