Significant damage has been reported over the eastern and north-western parts of the Free State, eastern and south-eastern part of the North West where at least 50 homes were impacted by the adverse weather conditions as a result of the first spring thunderstorms.
The South African Weather Service (Saws) said there was also wind damage reported at Moruleng Mall near Rustenburg and trees uprooted and damage at farms in the Free State.
“These storms are characterised by widespread strong, damaging surface winds and modest amounts of rainfall,” Saws said in a statement.
It added that radar and satellite remote sensing data provided little or no indication of the possible severity of the storms, however, a significant feature was that given the very dry conditions at the surface, the convective cloud base of the thunderstorms was at an abnormally high altitude above the ground.
🔴 BREAKING: MULTIPLE REPORTS OF STRUCTURAL DAMAGE IN PARTS OF PRETORIA, DUE TO STRONG WINDS ASSOCIATED WITH STORM | 📸 YUSUF ABRAMJEE pic.twitter.com/aAYYCCGhiC— Gauteng Weather (@tWeatherSA) September 19, 2023
Near HURRICANE force wind gusts last night in Pretoria 💨💨— Vox Weather (@VoxWeatherZa) September 20, 2023
19 September 2023
⚡️⚡️Severe Storms in South Africa causing damages in North West, Gauteng, the Free State and KwaZulu-Natal #weatherforecast #thunderstorms #gauteng #southafrica #strongwinds #greenscreenvideo pic.twitter.com/xl86H217Qj
“While this type of storm development can occur at any time of the year, early summer season storms are notorious in terms of frequently being associated with strong, damaging winds caused by microbursts or dry thunderstorms,” Saws said.
What is a microburst
Saws explained a microburst as a localised column of sinking air or a downshaft inside a thunderstorm that is usually around four kilometres in diameter.
“With a dry microburst, the precipitation evaporates upwards inside the downdraft, causing the downdraft air to become colder and denser and this accelerates the cold air towards the ground, influenced by gravity.”
Gale winds were reported in Harrismith, Free State as well as the North West and in Gauteng, Soshanguve, Mamelodi, Pretoria and Centurion.