Pretoria - Flash floods wreaked havoc in Pretoria east on Monday and in Joburg and Ekurhuleni two days later - but it was only just the beginning, according to the South African Weather Service.
Weather forecasters on Thursday predicted thunderstorms and flash floods for Pretoria heading into the weekend. They warned the public to take extra care at all times.
“There remains a very high risk of heavy rain which will result in flooding in more places,” meteorologist Christina Thaele said.
Motorists remain the most vulnerable in flash floods, and experts warned to avoid flooded areas and to not cross bodies of water even if it looked possible, to avoid a repeat of chaotic scenes witnessed in the city and in Joburg this week.
The trick was to drive as slowly as possible and pull to the side of the road as the city braced for possible thunderstorms and flash floods, said Thaele.
The rain was expected to fall across Gauteng, including Pretoria, as well as the north-eastern Free State, KwaZulu-Natal, Mpumalanga, eastern North West and Limpopo.
“Listen to the special warnings and pay particular attention to times and places,” Thaele said.
Six people died and many were displaced after their homes were flooded or washed away when the province was hit by extreme floods in parts of Joburg and Ekurhulen. Cars were swept away and many more damaged as water levels swelled in a short period of time.
The provincial government on Thursday provided temporary shelter for some as a mop-up op started.
A flash flood is the rapid flooding of a low-lying area, caused mainly by heavy rain associated with a severe thunderstorm, hurricane or tropical storm. They differed from regular floods by a time-scale of less than six hours, weather experts said, adding that flash floods were rare but wreaked havoc.
“It is sometimes not always possible to be warned that these deadly, sudden floods are coming,” emergency services ER24 said.
A massive thunderstorm, accompanied flash-floods hit Silverlakes in Pretoria on Monday, flooding rivers and streams and trapping people in cars and buildings.
The floods left vehicles stuck at low water bridges, and about 30 vehicles were trapped when the basement parking of an office park was completely flooded.
“The massive flash floods caused serious damage to infrastructure, and signboards, pavements and road surfaces were uprooted,” mayor Solly Msimanga said.
The weather service said Monday’s storm was the result of a cloud burst that lasted an hour and released 104mm of rain.
Motorists must remain calm, unbuckle seatbelts and drive very slowly with headlights on if caught in storms and flash floods, the Automobile Association of SA (AA) said.
“The most important factor is trying to avoid floods. Paying attention to traffic reports and looking for alternate routes to avoid danger are among the first steps to take, the AA said.
If in a flood, turning around and driving away from the flooded area was most advisable. If not possible, drivers should gauge the depth of the water before venturing forward.
Mandy Barrett of Aon insurance brokerage and risk advisers said: “Never attempt to drive through a flooded area of the road; even a few centimetres of water is powerful enough to sweep a car away.”
She said getting to safety as quickly as possible was next, and people should get out of their vehicles and on to higher ground. “Don’t close all windows as the water will cause a vacuum and trap you in the car,” she said.
Slippery roads, potholes and tyre damage were contributors to accidents in stormy weather. Increasing following distance, reducing the speed limit, being on the lookout for swerving motorists and to be wary of traffic lights not working were on the list of things to do.
Motorists were also advised to obey authorities and follow instructions from emergency personnel.
The country was headed towards a La Niña phenomenon and an extremely rainy summer and storms for the November to January months. Flash floods could occur at regular intervals, the weather service warned.
Heavy rains fell again east of the city on Thursday night, and the electricity was off in the affected areas.
MMC for Infrastructure Darryl Moss said the city had necessary infrastructure to mitigate the effects of the downpours. “However, our infrastructure cannot entirely prevent flash floods on the roads or in our homes. We urge residents to be cautious and act responsibly if caught in a flash flood.”