The tornado that decimated parts of oThongathi and the province last week has been described by the South African Weather Service (Saws) as the most severe experienced in the country in 25 years.
Over 7 000 households have been affected in KwaZulu-Natal following devastating floods, with over six districts in the province suffering damage.
A total of 12 people died after the tornado hit, and damage costs are estimated at more than R1.3 billion.
The Saws said a post-severe weather assessment found that the tornado was rated EF3 on the Enhanced Fujita (EF) scale, with estimated wind speeds of 225 to 265km/h that blew off roofs, damaged infrastructure and uprooted trees.
Based on the estimated wind speed and observed damage by using various damage indicators, the EF scale enables the classification of tornado events. The scale consists of 0 to 5 EF ratings, 0 being “minor damage” and 5 being “incredible damage” where nearly all buildings are destroyed. The oThongathi tornado sits right in the middle of the scale.
According to Saws, most tornadoes in South Africa are weak, with a low EF rating of 0 to 2. The stronger and more destructive tornadoes (EF3 and EF4) occur every decade or so.
“One of the highest-rated tornadoes in South African recorded history was the Welkom tornado of March 20 1990, rated as an F4 on the Fujita scale, resulting in damage to 4 000 homes, and was one of the costliest in history. In 1999, an F4 tornado struck Mount Ayliff. This tornado threw cars and trucks into the air and left 95% of the population in the area homeless,” Saws said in a statement.
The weather service said that a wedge tornado developed in oThongathi and moved east to the coast near Westbrook and Ballito, where it caused significant damage.
“Wedge tornadoes are usually larger and wider from the surface to the cloud base or, in other words, they are wider than they are tall. Wedge or wide tornadoes are often (but not always) categorised as strong tornadoes.”
Saws also addressed the concerns of whether these types of weather systems are associated with climate change.
“It is safe to say that, although a singular weather event cannot be directly correlated to climate change, climatologists agree that these types of weather systems may become more frequent and intense in the future due to a warming climate.”
The Mercury