The ongoing drought, combined with strong frontal winds is causing the dust to hit the city, said the Associate Professor at Sydney Institute of Agriculture.

"These large rolling dust storms we occasionally see in eastern Australia are a culmination of periods of drought that have left very little surface vegetative cover intact, combined with vigorous frontal wind systems that sweep from west to east across southern Australia," he said.

"Such events have always happened in eastern Australia in times of prolonged or severe drought - for example, multiple times between 1895 and 1945 - but with climate change affecting rainfall distribution and temperature fluctuations in eastern Australia, I think it's more than likely that such dust storm activity will become more frequent."

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Multiple dust storms have hit the Central West in recently weeks, including one that was so severe it turned the sky black.

But Associate Professor Cattle said there was "not much" that could be done to prevent them.

He said more dust storms could be expected to hit the region until the drought is broken.

"Even if the drought breaks in [regional NSW] tomorrow, if it hasn't rained further west in the dust source areas then the dust storms are likely to continue," he said.

"Regarding severity, once the soil surface is bare it depends on the wind speed as to how severe the dust storm is. The recent spectacular dust storms have been the result of quite vigorous fronts moving across NSW."

Groundcover is the best way to prevent wind erosion and therefore the dust, but Associate Professor Cattle said when there wasn't significant rain for two years combined with periods of very high temperatures, maintaining vegetative groundcover like grasses became very difficult.

"While a single event dust storm might only strip a millimetre or two of surface soil, this is usually where the most soil organic matter sits, so wind erosion usually represents a loss of potential plant nutrients from the topsoil," Associate Professor Cattle said.

"Over time, and with repeated wind erosion, entire topsoils can be lost, reducing the productive potential of the land in the dust source region."