Visible from space: The wall of dust marching across the Australian outback to turn the skies over Sydney blood red

It is a city that usually wakes to brilliant blue skies. But dawn broke with a dramatic difference in Sydney yesterday. 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 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. However, the eerie scenes haven't caused all activities to cease - the iconic Bondi beach still had its surfers and children continued to play on swings in the city's parks.

The storm, which blacked out the mining town of Broken Hill on Tuesday before sweeping east, was caused by a major cold front whipping up the dust from the drought-stricken hinterland. (Daily Mail)