"Paramedics were responding to a truck accident near Mooi River when the vehicles became bogged down in the heavy snow," Netcare 911 spokesperson Chris Botha said at 02:30.
"At the moment they can't move. Disaster management and a toll concession team have gone to assist them but we will wait for daylight to see how to get in there to get them out."
‘Don’t leave vehicles on foot’
Botha said a four-by-four ambulance arrived at the scene and transported an injured man to a local medical facility for further treatment.
Emergency services urged motorists to stay out of the area until the roads are cleared.
"If you do get trapped in the snow, please don't leave the vehicle on foot, stay where you are until help arrives to assist you to safety," he said.
Botha said no other people were injured.
Meanwhile, parts of the N3 toll route between Johannesburg and Durban were closed on Wednesday morning due to the snowfall, the N3 Toll Concession said.
"We have had to close the N3 toll route from the Wilge Toll Plaza to the Cedara Interchange near Hilton in KwaZulu-Natal," spokesperson Andy Visser said.
‘Don’t travel in bad weather’
Visser said they needed to ensure the conditions were safe before they could send emergency vehicles to assist stuck motorists.
"We understand that it is a long weekend, but we urge motorists to please not travel until the weather conditions improve in the interests of their safety," Visser added.
Meanwhile, Johannesburg metro police spokesperson Chief Superintendent Wayne Minnaar urged motorists to be extra vigilant as more rain was expected.
"Roads are slippery when wet, motorists should reduce travelling speed, keep their headlights on and maintain a safe travelling distance when it rains," said Minnaar.
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