1. Sydney Dust Storm 2009
September 23, 2009

2. Bureau of Meterology
A major dust storm with strong winds hit Sydney during the morning of 23rd September producing a blood red sky and reducing visibility to 400 metres over much of the city. A thick layer of red dust coated all exposed surfaces with many flights delayed or cancelled at Sydney Airport. It was Sydney's worst dust storm since 1942.

3. Statistics….
The dust storm was 500 kilometres in width and 1,000 kilometres in length and covered dozens of towns and cities in two states.
By 24 September, it measured the distance from the northern edge at Cape York to the southern edge of the plume to be 3,450 km.
Air particle concentration levels reached 15,400 micrograms per cubic metre of air. Normal days register up to 20 micrograms and bushfires generate 500 micrograms. This concentration of dust broke records in many towns and cities.
The CSIRO estimated that the storm carried some 16 million tonnes of dust from the deserts of Central Australia, and during the peak of the storm, the Australian continent was estimated to be losing 75,000 tonnes of dust per hour off the NSW coast north of Sydney.[

4. Source and distance

5. Red alert as big dust storm blankets Sydney
Eight years of drought and record temperatures that have baked outback soils bone-dry were blamed for yesterday's dust storm that turned Sydney's sky red and the sun blue.
Scientists estimated 75,000 tonnes of dust were being blown across NSW every hour in what may have been the most severe dust storm Sydney has seen since the droughts of the 1940s.
Department of Environment and Climate Change scientist John Leys said NSW was experiencing ''something like 10 times more dust storms than normal''.
''In the last two months we have been getting a major dust storm once a week,'' he said.
NSW Bureau of Meteorology regional director Barry Hanstrum said rain in the past six months over the border region covering far north-west NSW, north-east South Australia and south-west Queensland was in the lowest 10 per cent on record.
With the soil so dry, whenever strong winds blew ''you would have a dust storm, any time'', he said.
Sydney University soil scientist Stephen Cattle estimated yesterday's dust storm stripped several millimetres of topsoil from hundreds of square kilometres of NSW farms. ''This will reduce the productivity of their soil, certainly,'' he said.
By noon, satellite imagery showed the dust stretching over thousands of kilometres, from the Victorian border, north to Goondiwindi and Bundaberg in Queensland.
Scientists are already studying tell-tale red dust that fell over New Zealand's snowfields last week.
Air quality in Sydney's east yesterday was about 40 times what is regarded as ''poor'' and about 20 times the ''hazardous'' level - the worst conditions in about 70 years.
The Health Department advised people not to exercise - even indoors - and sent an advisory to preschools and schools to keep children inside.
The director of the Environmental Health branch of NSW Health, Dr Wayne Smith, said the pollution was as bad as a ''heavy bushfire'' day.
A NSW Health spokeswoman said there was a ''significant increase'' in the number of people going to hospital emergency departments and some hospitals had to set up respiratory clinics.
Red alert as big dust storm blankets Sydney
RICHARD MACEY AND NATASHA WALLACE
September 24, 2009

6. Satellite images

8. Path of the dust storm

10. Sydney Tower