A spectacular computer-generated dust storm in the new Mad Max movie provides a novel backdrop for a car chase. If you see one approaching in your rear-view mirror it is theoretically possible to escape by driving fast, though this is not recommended in real life because of the risk of accidents.
Dust storms are most dangerous when they strike a road at right angles. When this happens visibility suddenly drops to zero for a long stretch of the road, creating the potential for multi-vehicle pile-ups. The advice to drivers is to pull over in a safe place and wait for the storm to pass.
To the driver the dust storm may just be an exotic fog, but it is actually much more damaging.
Unlike a sandstorm, which whips up large grains from the surface, a dust storm transports quantities of fine sand and leaves a thick deposit in its wake.
In China, such dust storms are known as black wind and they can be very destructive. A storm during May 1993, around Inner Mongolia, killed hundreds of people, and many more were reported missing. The storm blocked roads, brought down power lines and filled 2,000 kilometres of ditches with sand. It also destroyed thousands of hectares of crops.
The black wind sometimes reaches to the capital, Beijing. Last month the city was darkened by the worst dust storm for a decade. The pollution levels soared and traffic came to a halt in the thick haze – providing a vision as apocalyptic as anything imagined by the makers of Mad Max.
