Sun Oct 16, 2011 11:01pm EDT
* Australia weather bureau says country faces more than 12 cyclones 2011-12
* Oil, gas, as well as coal and iron ore mines may be at risk
* Another La Nina weather pattern brewing to fuel storms
SYDNEY,Oct 17 (Reuters) - Australia faces an above-average number of cyclonesover the coming storm season, meteorologists said on Monday, threateningnew devastation after massive floods swamped homes, as well asdestroying crops and crippling mining earlier this year.
Thenorthwest offshore oil and gas field and coastal iron ore operationsface a 65 percent chance of being hit by more than seven cyclones,Australia's Bureau of Meteorology (BOM) said in its 2011-12 tropicalcyclone season forecast.
NortheastAustralia, where coal mining was crippled last year due to heavyflooding partly generated by cyclones, also faces a 65 percent chance ofmore than the average of three to four cyclones this season, said BOM.
Intotal, Australia's north may be hit by more than 12 cyclones due toneutral to borderline La Nina weather conditions, which bring wetweather to the western Pacific, fuelling tropical storms over the ocean.
"Historically, these conditions have favoured an above average number of cyclones in the Australian region," said BOM.
Australia's cyclone season is between November and April.
Naturaldisasters including floods and cyclones cut economic activity by 0.75percentage points in 2010-11, wiping A$1.75 billion from revenue across2010-11 and 2011-12, Treasurer Wayne Swan said.
Australia's third-largest city Brisbane was inundated with floodwaters and flooding across an area as big as France and Germany forced major miners to declare force majeure and damaged large swaths of croplands, including the key sugar crop.
Australia,one of the world's largest coal exporters, accounts for abouttwo-thirds of the global coking coal trade, with around 90 percent ofthat coming from Queensland state.
Coking or metallurgical coal is used for steelmaking, with the bulk of Australian exports to China.
Global miners Rio Tinto , BHP Billiton and Xstrata are among major companies involved in coal mining in Queensland.
Oneof the most powerful La Nina's in recent years fuelled the devastating2010-11 cyclones and floods and the bureau of meteorology said another,less powerful, La Nina would likely develop in 2011-12.
"Beforea tropical cyclone forms it is difficult to predict its exact strengthand path, including whether it will make landfall," said the bureau.
"Alongthe east and west coasts fewer than half of the cyclones affect thecoast, with most staying out to sea. Along the north coast more thanhalf of the cyclones impact the coast. Tropical cyclones which remainout to sea can still cause storm surges, gales and areas of intense rainover land."