It is a city that usually wakes to brilliant blue skies. But dawn broke with a dramatic difference in Sydney. Pulling back their blinds, residents were greeted with an eerie reddish-orange cloud cloaking all around them. Early-morning commuters stared in disbelief at the Sydney Opera House and Harbour Bridge, whose normally striking outlines were rendered ghostly by the shroud of dust.
The gale force winds - measuring in excess of 60mph - also fanned bush fires in the state. By noon on Wednesday the storm, carrying an estimated 5 million tonnes of dust, had spread to the southern part of Australia's tropical state of Queensland.
The dust storms stripped valuable topsoil from farmlands. At one stage up to 75,000 tonnes of dust per hour was blown across Sydney and dumped in the Pacific Ocean.'We've got a combination of factors which have been building for ten months already - floods, droughts and strong winds,' said Craig Strong from DustWatch at Griffith University in Queensland.
The outback dust storm has swept across eastern Australia, shrouding Sydney in a dramatic red glow. It's also been wreaking havoc, disrupting transport and placing health authorities on alert for widespread respiratory illness.
International flights were diverted from Sydney, ferries on the harbour were suspended, and motorists were warned to take care on roads as visibility was dramatically reduced.'It did feel like Armageddon because when I was in the kitchen looking out the skylight, there was this red, red glow coming through,' one resident told Australian Broadcasting Corporation radio.
The blanket of dust stretched hundreds of miles along the coast, from the coal port of Newcastle north of Sydney to the steel city of Wollongong in the south, and hundreds of miles inland to farming towns like Dubbo and Tamworth.
Weather officials said the blanket of dust would remain for several hours, until winds eased.
Further cold fronts are expected later in the week and could bring not only more strong winds, with the chance of dust storms, but also snow falls higher up on Australia's mountain region, said weather officials.
Dust storms in Australia are not uncommon but are usually restricted to the inland. Occasionally, during widespread drought, dust storms reach coastal areas. Australia is the driest inhabited continent and only Antarctica is drier.
The NSW state government recently cut the state's 2009/10 wheat crop estimate by 20 per cent because of hot, dry weather across the grain belt.The country is one of the most vulnerable nations to climate change, but also the world's biggest greenhouse gas emitter per capita as it relies on coal-fired power stations for the bulk of its electricity.
Australia is battling one of its worst droughts and weather officials say an El Nino - a periodic change in the atmosphere and ocean of the Pacific - is slowly developing which will mean drier conditions for eastern states.
The country is one of the most vulnerable nations to climate change, but also the world's biggest greenhouse gas emitter per capita as it relies on coal-fired power stations for the bulk of its electricity.