Flash floods have claimed the lives of dozens of South Africans around the country.
In simple terms: plan, be prepared act decisively.
What does a flash flood warning mean? Flash Flood Warnings are issued for flooding occurring within 6 hours of heavy and intense rainfall. An Areal Flood Warning are issued for flooding that occurs more gradually, normally from prolonged and persistent moderate to heavy rainfall longer than 6 hours.
A number of streams, like the Klipspruit River, Klip River, Jukskei River, Klein Jukskei, Braamfontein Spruit, to name a few, meander throughout the suburbs and cities of Gauteng. Though mostly canalized, they have the potential to overflow and burst their banks – causing devastating flash floods. Flash floods are sudden, violent and powerful enough, in 60cm of water, to lift even a truck. Did you know a flash flood of 10cm+ of rapidly flowing water is capable of washing your car away?
Radio stations, social media will issue flood warnings, areas and roads to avoid. This gives you a window of opportunity to prepare. Heavy and rapid downpours cause runoff that collects in gullies, streams and converge to form larger volumes of fast flowing water and debris – often miles away from the source. If you are on your way home from work, visualize the route; imagine that route/highway congested, and which spots, bridges, under bridges or river crossings that you need to avoid. This will help you decide on an alternative route, preferably towards higher ground. If you have little ones in the car, at all costs steer-clear of all congested routes prone to flash flooding and absolutely avoid driving when it is dark.
Floods and flash floods are often unavoidable – in which case you need to remain calm and focus: if you see the water rapidly rising in relation to the height of your window – unbuckle, open your window and get out. Do not let your car fill with water, the car will sink faster and you and your passengers will drown – with the force/pressure of the outside water you will not be able to open the door. Your window is your only option and if you find yourself in water deep enough to sink your car; you have thirty seconds to get out. Keep your safety belt on until the appropriate time to unbuckle yourself – a flash flood can cause your car to roll. If possible, protect your cellphone from getting wet and use it outside the vehicle – this is no time for selfies. You will have to stand aloft your roof until emergency services arrive – otherwise attempt to get too higher ground as quickly as possible.
Exploding urban development, more concrete, more tar and poor drainage have reduced the city’s capacity to absorb rainwater – our stormwater drainage system cannot cope and there are less natural land or veld areas to soak up all the water. South African motorists must beware that as infrastructure goes up, so will the frequency of flash floods.