- Tropical Cyclone Freddy made landfall in Madagascar on Tuesday with at least four people dead and 16 600 being affected.
- The weather system has weakened over land and is now classified as a severe-to-moderate tropical storm.
- Itis expected to move through the Mozambique Channel and again make landfall onFriday, affecting the north-eastern regions of South Africa too from Saturday.
Tropical Cyclone Freddy has weakened after it lashed the eastern coastof Madagascar on Tuesday.
The SA Weather Service (SAWS) has confirmed "Freddy weakenedsignificantly due to the rugged terrain it encountered and was downgraded to anoverland depression during the evening".
SAWS forecaster Lehlohonolo Thobela told News24 "it went overland,and it lost much of its energy as it made landfall over Madagascar. It'sexpected to regain most of the energy along the Mozambique Channel as it movesover".
READ | Intense cyclone Freddy lashes Madagascar, kills one
Thobela said as it entered the channel it would be a moderate tropicalstorm but when it made landfall in Mozambique it would most likely be a severetropical storm.
Professor Jennifer Fitchett of Wits University's school of geography addedtropical cyclones, including Freddy, would most likely not make landfall inSouth Africa based on current forecasts and historical data.
"South Africa is unlikely to experience the landfall of tropicalcyclones due to the latitudinal position, and the protection offered by theMadagascan landmass," she added.
Professor Livhuwani Nemakonde from the African Centre for DisasterStudies at North West University added South Africa was somewhat fortunatebecause "when they do landfall in parts of Mozambique, as it progresses itbecomes weaker. Mozambique and Madagascar are the ones that feel the full bruntof these cyclones".
Difference between tropical storm and tropical cyclone
The severity of the winds is what usually classifies the intensity of atropical weather system like a cyclone.
As it moved into Madagascar, the SAWS, in a statement on Tuesday, said"the relatively compact storm was a low-end category 2 tropical cyclone justbefore making landfall, with winds of 150km/h and gusts up to 180km/h".
Thobela added a "severe tropical storm is between 89km/h and118km/h, should it go above that it becomes a tropical cyclone".
Hesaid before it made landfall it was regarded as a severe tropical cyclone withwinds of 200km/h and above.
Impact of a tropical storm on South Africa
"The north-eastern regions of South Africa are forecast to receivesome rainfall associated with the outer cloud bands of the storm. This isunlikely to be severe in nature," Fitchett said, adding only the SAWS couldissue weather warnings.
Thobela said no severe warnings have been issued yet but they wereexpecting rain in the north-east of Limpopo and the Lowveld of Mpumalanga.
He added severe weather warnings were evaluated based on the"vulnerability of an area and how the system will move over it".
Recent flooding in Limpopo and Mpumalanga make those regions morevulnerable with the weather service issuing level 2 warnings at the time after heavyrainfalls.
WATCH | All the latest videos on tropical Cyclone Freddy
Thestatement on Tuesday from SAWS added:
Very heavy rainfall in the order of 200 to 400mm is possible, and this may result in widespread significant flooding. The districts in question are Vhembe and Mopani in Limpopo, and to a slightly lesser extent, Ehlanzeni in Mpumalanga.
Nemakonde said these regions would feel the impact of the cyclone evenif it was weaker, especially given the recent flooding in those areas.
"This system when it falls on a fragile area will have a hugeimpact for the people who are still dealing with the disaster of the past fewweeks."
How are tropical cyclones formed
Fitchett added for tropical cyclones to form, sea surface temperaturesabove 26 degrees Celsius were required, while another condition of formation waslow vertical wind shear (the difference between the wind speed and direction atthe land surface, versus the upper air).
Shesaid:
Climate change is resulting in the gradual warming of both air temperatures and sea surface temperatures. This means that those threshold temperatures of >26 degrees Celsius occur more often and over a larger area, thus meeting the requirements of the conditions of formation.
However, "under climate change, vertical wind shear is increasingin many regions. This inhibits the formation of tropical cyclones. The resultis that fewer tropical cyclones are forming in the South Indian Ocean, butthose which do have warmer waters to strengthen them".
Fitchett added "the primary impacts of climate change, andparticularly sea surface warming, is in the intensification of tropicalcyclones [which in turn affects the maximum wind speed, size of the storm, andtherefore the amount and area of devastation], and the pathways followed, withan increasing number of higher intensity tropical cyclones being detectedfurther from the equator".
READ | Why experts regard Turkey and Syria earthquakes asunsurprising... and how you can help
As tropical cyclones continued to track further poleward, she said,"and as they increase in size, it does heighten the overall risk for SouthAfrica".
However, predicting when cyclones would cause severe impact to SouthAfrica or if they would ever make landfall on South Africa was not possible,"it is important rather to monitor the forecasts of individualstorms," Fitchett added.
Impact of climate change and can SA deal with the devastation
Regarding the devastation these weather systems can cause, she said,"tropical cyclones result in severe winds and flooding, which evendeveloped countries struggle to withstand".
Nemakonde added South Africa had good disaster management protocols onpaper but in practice it was just not capacitated or funded enough.
Hesaid:
I'm not really sure our country is really prepared to deal with them.
Nemakonde added the human impact and loss was something to consider -especially when people, who have not had rains build, next to riverbanks orfloodplains.
"The impact in those locations will be high because of theexcessive water and winds. It is important for us to reduce this impact bydealing with the human element."
Heechoed Fitchett's sentiments in that climate change was intensifying tropicalweather systems like this, adding "normally at the end of January throughto mid-March is the period when this region in Africa experiences much of thesecyclones".
