The white dust that greeted people in the greater Johannesburg area on Tuesday morning might be from as far as the Kalahari desert, the Witwatersrand University’s School of Geoscience said.
Prof Harold Annegarn said he was investigating the possibility that the very strong winds over the interior had brought the dust to Gauteng from the Kalahari, hundreds of kilometres away.
”The dust could quite easily be from as far away as the Kalahari,” he said. ”We have taken samples and will test them.”
During this time of year Gauteng experiences strong winds as the seasons change from winter to spring. However the winds on Monday were gustier than usual.
Annegarn said the dust, which was seen in the skies from Monday morning, was cleaned from the air during a rain storm on Monday night.
”Because the rain did not last long, the dust was not swept into the gutters… and that was the reason for freckles (of dust) on the cars this morning,” he said.
Dust is brought into Gauteng from far-lying areas about once every five or six years.
An SA Weather Service employee said it was not likely that the dust was from the Kalahari.
Aubrey Mofolo said the service believed the dust was due to smoke from veld fires which was trapped by a high pressure subsiding.
However both men were in agreement that some of the dust was from the dozens of mine dumps in the area. – Sapa