Wild weather ahead- A land of droughts and flooding rains
by Jeni Bone on 13 Jan 2011
Experts are forecasting a major Cyclone to hit the Queensland coast including the Far North, sometime around Australia Day, 26 January.
Tropical Cyclone ..
As far back as July 2010, meteorologists were predicting unusually wet weather for much of the east coast, when the early stages of La Niña appeared. The bad news is, there's more to come, and rain-sodden Australia can only expect La Niña to run out of steam in Autumn (around April), when the system will ease off.
Comparisons with 'the floods of 1974' were inevitable. Many Queenslanders, especially in Brisbane, still have the flood levels marked on their garage walls as a reminder. So far, flood levels have remained a metre below the 1974 peak of 5.45m, but an increased population, much more development – much of it concrete on flood plains – have meant the impact and devastation are many times worse.
1974 was a major year for catastrophe in Australia. Off the back of the wettest year ever in1973, and in keeping with the strong La Niña event that prevailed, the 1973/74 northern wet season started early. By the end of 1973 large areas of the country were saturated. Then came January 1974, which featured probably the biggest continent-wide drenching since European settlement, inundating vast areas of the country.
Queensland and northern NSW suffered enormous damage from Tropical Cyclone Wanda around the Australia Day long weekend.
That season created chaos and inundation that lead to the Coast's biggest rescue operation to that time and 1500 people were evacuated, many houses were destroyed and cars swept away.
Then was Cyclone Tracy Christmas Day which obliterated Darwin, destroying 70% of its buildings and killing 71 people.
Alex Zadnik, a meteorologist at The Weather Channel, predicts about 15 tropical cyclones to form in Australian waters over this wet season (September to April) and said about half would be likely to cross the coast.
Mr Zadnik said the active weather was the result of a La Nina weather pattern during which cyclone activity usually increased by 50 per cent.
'During a La Nina year, we see warmer than usual sea surface temperatures around northern and eastern Australia,' he said.
'In turn, this increases the chance of tropical cyclones.'
Much of the problem lies in the urban planning of our towns and cities, which have undergone unprecedented building programs to accommodate residential expansion.
Dr Rob Roggema, a Research Fellow in the Climate Change Adaptation Program within RMIT University's Global Cities Research Institute, Landscape Architect/Planner and an inaugural visiting fellow at the Victorian Centre for Climate Change Adaptation Research, says this episode of major flooding can be attributed to poor planning practices and 'Increased concrete surfaces'.
'Recent planning practice has contributed to the magnitude of the flooding disaster in Queensland. In current planning practice, the amount of concrete surface is increased – leading to a much higher runoff than before – while increasing water storage capacity is not a major factor in compiling spatial plans and new buildings are placed in vulnerable places.'
He urges spatial planners and designers to take in to account these kinds of disasters, since the amount of runoff water is increased and many more people are placed at risk.
'If we are to learn from this for the future, we must create a long-term strategic and anticipative plan for Queensland in which new buildings are positioned in the least flood prone places, the water storage capacity of each catchment is calculated on twice the worst predicted event and the amount of non-permeable surface is halved – instead of literally rebuilding everything in exactly the same places and in exactly the same way.
'That kind of rebuilding does nothing to help communities adapt to future risks, but simply leaves these areas just as vulnerable to the next disaster of an even greater magnitude.'
More at http://www.bom.gov.au/lam/climate/levelthree/c20thc/flood7.htm
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