Climate change: New study reveals alarming flood and storm patterns in KwaZulu-Natal

IOL News

19-06-2025

The April 2022 floods left hundreds dead and caused a trail of destruction to infrastructure, businesses, homes, and communities.
Image: Doctor Ngcobo / Independent Media
In a stark revelation about climate challenges facing South Africa, a comprehensive study analysing weather-related disasters over the past 43 years has identified floods and storms as the most pervasive threats, particularly impacting KwaZulu-Natal (KZN).
This was announced just days before severe weather struck, causing at least 90 deaths due to flooding in the Eastern Cape. Torrential rains and freezing temperatures also lashed KZN, where flooding events have become a tragic norm following the tragic devastation of the April 2022 floods.
With research led by Mary-Jane Bopape, managing director of the South African Environmental Observation Network (NRF-SAEON), the study sheds light on the urgent need for enhanced climate resilience strategies in a province grappling with the devastation of heavy rainfall.
The research, utilising extensive data from the Emergency Events Database (EM-DAT), along with information from the South African Weather Service and European weather forecasting systems, has highlighted KZN's position as the most disaster-prone area, specifically the eThekwini Metropolitan Municipality, which has recorded the highest number of these weather-related events.
Flood-related events were the most common during this period, occurring 49 times, followed by storms, which were reported 33 times.
The study noted that this pattern is consistent with global disaster trends, where hydrological and meteorological hazards are the most frequently recorded natural disasters, according to the EM-DAT methodology.
Weather-related disasters in South Africa from 1980 to 2023 were published in the Environmental Development journal by Mary-Jane Bopape, managing director of the South African Environmental Observation Network (NRF-SAEON), and her team.
Image: Supplied
Flooding includes riverine floods, which occur when rivers overflow, and flash floods, which are caused by intense, short-duration rainfall. Storms are diverse events, such as landfalling ex-tropical cyclones (frequently bringing floods and high winds), convective storms with tornadoes, lightning, and severe thunderstorms, as well as winter storms.
'With these insights, we can better inform climate resilience strategies and proactive disaster management efforts. This important contribution to the field paves the way for more effective responses to climate challenges and disaster preparedness in our communities,' Bopape remarked, emphasising the research's potential impact.
The study found that, although KZN receives substantial rainfall, no evidence suggests that eThekwini experiences more rainfall than other districts in the province, which 'suggests human influences associated with urbanisation in disaster patterns'.
KwaZulu-Natal is bordered by the Indian Ocean to the east and the Drakensberg Mountains to the west. The province has experienced numerous flood-related disasters, it said.
Tropical cyclones have caused some of the most damaging events in the region. For example, Domoina in January 1984 brought extreme rainfall to northern KwaZulu-Natal, Swaziland, and eastern Mpumalanga. Analysis of events from 1984 to 2019 indicates that most of these were due to tropical lows.
The region is also highly susceptible to severe convective storms, with the eastern coastal zone as a hotspot for these events due to its proximity to the Agulhas Current, which provides significant latent heat for convection.
Cut-off low systems, known for causing prolonged heavy rainfall, have been linked to major floods like the April 2022 disaster and other historical flood events in the country.
'The catastrophic April 2022 floods in Durban caused extensive damage to infrastructure and claimed over 430 lives, making it the worst flood disaster in South Africa's history,' stated the study.
It also found that the Cape Town metro reports the highest number of disasters in the western part of the country, associated with more rainfall, yet human factors may also contribute.
Weather Systems responsible for floods and storms in SA from 1980 to 2023 with abbreviations indicated as follows: cut-off lows (CoL), upper troughs (UT), surface troughs (ST), ex tropical cyclones (ETC), upper perturbations (UP), surface lows (SL) and continental low (CTL).
Image: Supplied
It emerged that cut-off low systems and upper troughs, which are classified as mid-troposphere mid-latitude systems, triggered the most floods and storms, while ex-tropical cyclones (ETCs) caused only four disasters during the study period.
However, the study noted that upper perturbations, which are disturbances in the upper atmospheric flow pattern usually associated with clouds and precipitation, also resulted in floods and storm disasters, indicating a need for forecasters to also pay attention to smaller-scale processes, the study found.
'These findings enhance our understanding of weather-related disaster risks in South Africa, providing valuable insights for climate resilience and proactive disaster management.'
It stated that South Africa is among the most disaster-prone countries on the African continent and ranks among the nations with the highest exposure to extreme weather events.
South Africa and Libya experience the most significant economic losses from disasters in Africa, according to further economic analyses.
The study indicates that coastal cities in South Africa have experienced a statistically significant increase in flooding. This rise is attributed to a combination of natural occurrences and human-induced factors such as insufficient urban drainage systems, rapid population expansion, and improper land-use strategies.
In 2022, according to the study, there was a doubling in the record number of reported flood disasters, amounting to a total of eight incidents, giving a record number of disasters reported in a year.
'Four flood disasters were documented in 2019 and 2023, with three occurrences in 2000. It is noteworthy that until 1996, the number of reported flooding disasters did not exceed one.'
Droughts ranked third, with a total of 11 reported events. Unlike floods and storms, droughts do not have subcategories in EM-DAT. It was reported that all municipalities in South Africa experienced drought over the past three decades, with rain-fed farming suffering more than irrigated farming.
Climate change projections indicate an increased risk of drought due to reduced mean precipitation across much of southern Africa, attributed to global warming, it stated.
Consequently, proactive measures such as reducing land degradation and enhancing dam and irrigation capabilities are essential.
Wildfire disasters were reported 10 times, nearly as frequently as droughts. These have been associated with droughts and the proliferation of invasive alien plants. During the analysis period, only three temperature-related disasters were reported, comprising two cold spells (July 1996 and May 2007) and one heatwave (January 2016).
The cold spells are generally associated with mid-latitude systems, including cold fronts, cut-off low (CoL) systems, and upper troughs and occasionally Type S ridging Atlantic high-pressure system, which all act as mechanisms to transport cooler air from the poles to the north impacting the subcontinent.
Both cold spells were associated with a CoL system, while the May 2007 event is also associated with a Type S ridging high. South Africa has experienced numerous environmental disasters in the past three decades, including droughts, wildfires, geological events such as earthquakes/tremors and temperature extremes.
'Droughts have been the most frequent, significantly impacting agriculture and likely to worsen with climate change. Wildfires are often linked to droughts and exacerbated by invasive plants.'
Geological events, though less frequent, have caused damage and casualties while temperature extremes have been less reported but show a trend towards more frequent heatwaves.
Overall, the study found that South Africa faces increasing disaster risks due to climate change, requiring proactive measures such as infrastructure strengthening, sustainable land management, improved public health, and better early warning systems.
[email protected]