CANBERRA - The vast dust clouds driven by violent storms that turned the skies of New South Wales and Queensland red yesterday may be a harbinger of things to come.

Weather forecasters are predicting another storm front for tomorrow, and warn that an emerging El Nino and land dehydrated by a decade of drought could produce a series of storms ripping topsoil from Australia's fragile interior.

There have already been three large dust storms in the past three weeks in the region around South Australia's vast Lake Eyre - where much of yesterday's dust was generated - and last week clouds of granulated red earth were blown to New Zealand.

Some of yesterday's cloud, which engulfed most of NSW and southern Queensland, will also cross the Tasman: thousands of tonnes of dust an hour is estimated to have been pumped across NSW.

The Bureau of Meteorology said this was one of the worst since the 1940s, when dust storms cloaked much of the continent's southeast and forced Adelaide to use street lighting in the middle of the day.

Chris Eiser, of the NSW Environment Department, told ABC radio that measurements of particle pollution were 10 times the worst on record.

Worse may be in store.

Although large dust storms are relatively common in Australia and researchers are reluctant to link recent events to climate change, forecasts predict that global warming will cause more droughts and similar storms.

Yesterday's red clouds were driven north from South Australia by a front that caused chaos and flash flooding in Adelaide, and triggered a tornado in the north of the state.

It ripped across Victoria and NSW with gales gusting to 100km/h, thunderstorms, and hailstones sometimes as big as cricket balls.

As it hit the mining city of Broken Hill in far western NSW on Tuesday, the front ripped out trees, damaged homes and closed roads.

Two miners were trapped underground for almost 24 hours when power supplies were knocked out.

As Canberra was blanketed by a deep, dark mist that cloaked landmarks such as Parliament House and the War Memorial, and dumped layers of dust across the capital, winds ravaged fruit crops and bombarded the town of Crookwell with hail heavy enough to smash roofs and damage cars.

Dust was whipped from Lake Eyre in a repeat of the 1983 storm that lifted 50,000 tonnes of topsoil from Victoria's Mallee region, formed it into a cloud extending thousands of metres into the atmosphere, and dumped 1000 tonnes on Melbourne.

Nasa satellite imagery showed the impact of a similar storm in 2002, capturing two enormous plumes of dust spiking out of Lake Eyre into southern Queensland.

As yesterday's storm moved north, it stripped farmland of thousands of tonnes of topsoil, hitting crop and pasture prospects and causing damage that farmers will take years to recover from.

Yesterday morning the front descended on Sydney, rolling across Australia's biggest city with a density that reduced visibility in some areas to just metres, obscuring the harbour in a red haze and triggering a tsunami of calls to emergency services and radio shows.

Callers to ABC radio said they awoke to a morning "like Armageddon".

Some said they had seen birds falling from the sky.

Health authorities told people with asthma, respiratory and other health problems to remain inside.

Ambulances responded to more than 100 calls from people experiencing breathing difficulties.

Unions closed construction sites, traffic was slowed to a crawl and city-bound lanes of the M5 east tunnel were closed, and flights at Sydney Airport - including some from New Zealand - were disrupted.

Fire brigades and emergency services were inundated by false alarms set off by dust interfering with electrical circuitry.

As the storm waned in Sydney, the front rolled through northern NSW into Queensland, where late yesterday forecasters predicted it would continue as far as the Gulf of Carpentaria.

As it descended on Brisbane, traffic slowed as visibility worsened.

Brisbane Airport remained open, despite a dust cloud that limited pilots' vision to 200m.

At sea, ABC radio reported that a helicopter had been sent to find a fisherman lost in the cloud off South Stradbroke Island, on the Gold Coast.

* The Sunshine Coast daily is covering the dust storm in their area.