Cyclones that have affected SA in the past 30 years

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Jumbo

Cyclones that have affected SA in the past 30 years

Unread post by Jumbo »

I’m trying to get info on the measured rainfall in Komatipoort…no luck yet :? …did however found this very interesting info on the Cylones that has impacted SA in the past 30 years 8)

Source: Weather sa

Which cyclones have affected SA in the last 30 years?

Tropical cyclones seldom reach South Africa. However a number of tropical cyclones do move into the Mozambique Channel and have an effect on areas surrounding the channel. The following are a few of the tropical cyclone that have had some effect on southern Africa:

Astrid (January 1958) – This tropical cyclone moved over Mozambique and passed north of Messina, eventually dying out over Botswana. Heavy rain fell over the Northern Province and Mpumalanga and severe flooding occurred over Wyliespoort.

Claude (January 1966) - Claude moved in over the country from Maputo, turned northwards and rapidly died out over Mozambique. Flooding occurred over Southern Mozambique with Maputo receiving 650 mm between 3 and 9 January. Komatipoort received 250 mm while Siteki received 400 mm.

Caroline (14 February 1972) – Caroline was active for a week in the Mozambique Channel, then moved inland at Inhambane and also weakened quickly. Heavy rains occurred over the Kruger National Park with between 68 to 158 mm being measured.

Eugenie (21-22 February 1972) – Shortly after Caroline, Eugenie also moved in overland at Inhambane, progressing as far as Messina. Heavy rain fell over the Northern Province and Mpumalanga with Levubu receiving 175 mm, Phalabora 75 mm, Barberton 82 mm and Piet Retief 84 mm.

Danae (27-31 January 1976) – This tropical cyclone moved in from the Channel between Beira and Inhambane on the 27th. By the 31st it was situated just west of Messina. From the 29th to 30th Fleur de Lys (Acornhoek) received 135 mm, Levubu 114 mm, Skukuza 108 mm and Louis Trichardt 60 mm.

Emilie (6-8 February 1977) - It moved in over Mozambique south of Beira, passing to the north of Messina and weakening over the central parts of the country. Flooding occurred over the Northern Province, Mpumalanga and KwaZulu-Natal. Down pours of more than 200 mm in 24 hours were reported in places over the Northern Province.

Kolia (March 1980) - Although Kolia only moved as far as the southern tip of Madagascar, heavy swells resulted along the KwaZulu-Natal coast.

Justine (March 1982) – This cyclone moved southwards in the Mozambique Channel and also never came close to the South African coast. However, heavy swells helped by spring tides caused damage to some buildings along the KwaZulu-Natal coast.

Domoina (29-31 January 1984) - This cyclone moved inland near Maputo resulting in severe flooding over southern Mozambique, Mpumalanga, Swaziland and KwaZulu-Natal. Rainfall figures of between 500 and 750 mm were measured over the 3 days over large areas.

Imboa (10 – 20 February 1984) - It moved southwards down the channel to the latitude of Cape St Lucia and then turned directly westwards to the coast. However, before reaching it, the cyclone curved south-eastwards out to sea again. Heavy floods occurred along the KwaZulu-Natal north coast and adjacent interior.

Eline (8-22 February 2000) - It started out as a tropical depression over 2500 km east of Mauritius on 8 February where the sea-surface temperature was in excess of 29 ºC. At the same time that this tropical depression was moving towards the coast of Madagascar and gaining strength, another tropical depression had moved in over the African continent at Beira, causing extensive rainfall and flooding in Mozambique, the Northern Province, northern and eastern Mpumalanga and southern Zimbabwe. Heavy rain also occurred in Botswana. This depression finally weakened around the 14th of the month. By this stage cyclone Eline had intensified and had reached the coast of Madagascar. As Eline moved in over Beira, the status of the cyclone had been upgraded to that of “intense tropical cyclone". Eline then moved inland towards Harare, weakening only slightly, but still causing heavy rains over the northern parts of South Africa, southern Botswana and Zimbabwe. The residual low from cyclone Eline passed as far west as the coast of Namibia before dissipating.


Have to say…some looks real scary…for example Claude (1966), where Maputo received 650mm rain in 7 days…Komatipoort 250mm during the same time! :shock:
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Re: Cyclones that have affected SA in the past 30 years

Unread post by Timepilot »

And Demoina which completely changed the face of Sodwana in '84!

I had been there 3 times in '83 with the last time being NY 83/84 - came back again in '85 after a stint in CT and Zim and could'nt believe how it had changed!!
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Re: Cyclones that have affected SA in the past 30 years

Unread post by Meandering Mouse »

Jumbo, thanks for that information :thumbs_up:

I do believe that we might be heading for another "big one". The cyclical nature of the build up suggests that it will happen sooner rather than later.

I was staying in Hazyview shortly before the 2000 flooding. I remember watching persperation forming bubbles on my leg and just rolling down. It was so humid, I could hardly breathe. It felt as though I was wrapped in a wet blanket. The sligtest movement was a supreme effort. At that time I was super fit, so this was very scary.

Later that night, it sounded as if all hell had broken loose. :big_eyes: I have never seen an electrical storm like I did that night. My poor children were shivering in terror. Next few days, there was no electricity.

It certainly increased my respect for the weather.
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Tropical storms.

Unread post by gmlsmit »

Tropical storms

Some years ago we did a trip from South Africa up as far as Northern Kenya. Up there we had to cross the Equator and one of the ways the locals make some money is to demonstrate the difference between the movement of wind and water in the two hemispheres of the earth. Going a short way north of the equator a matter of a few metres, water poured down a funnel rotates in an anticlockwise direction Moving the same distance south of the Equator the water rotates in a clockwise direction.

This brings on the subject of tropical storms, called Cyclones in South Africa and Australia, Hurricanes in the West Indies and America and Typhoons in Asia. Driven by the Coriolis force, which is what spins water in different directions north and south of the equator, these tropical storms rotate in exactly the same way. Moving over warm tropical seas, heated air and moisture are drawn inwards and upwards in a low pressure system which rotates around a calm centre called the eye. These huge storms can be hundreds of kilometres across with an eye of 50 kilometres and winds of nearly 300 kilometres an hour. The whole system is driven forward by the prevailing winds.

Cyclones do an important job for the Earth. They help move heat from warm tropical places to the cooler temperate zone. This makes them an important part of the global atmospheric circulation mechanism. To do this, they typically form between 5 to 15 degrees latitude north and south of the equator.

In recent years we have seen some very powerful and destructive cyclones like the one that hit New Orleans. The severity of these storms is driven by water temperature and with global warming and the oceans heating up we are likely to see even worse cyclones.

Tropical cyclones can produce extremely powerful winds and torrential rain. They are also able to produce high waves which result in damaging storm surges. With a lot of human development along coastlines, these mega-storms cause a huge loss of life and damage to infrastructure as well as affecting food supplies.
An anticyclone is a high pressure system in which the wind generally travels downwards and outwards. Depending on where they form on the globe, they can bring clear weather, but can also cause desertification in hot dry areas and are responsible for heavy rains such as the monsoon.

A tornado is another low pressure system that is a violently rotating column of air in contact with both the surface of the earth and a cumulonimbus cloud. They are often referred to as twisters.

Tornadoes have been observed on every continent except Antarctica. However, the vast majority of tornadoes in the world occur in the so-called "Tornado Alley" region of the United States. They also occasionally occur in south-central and eastern Asia, northern and east-central South America, Southern Africa, north-western and southeast Europe, western and south-eastern Australia, and New Zealand.

Impact of tropical storms on nature.

The impact of tropical cyclones on coastal vegetation and wildlife can be devastating. Winds that can attain speeds of well over 200kms per hour, rip through coastal shrub and forest, in some cases removing it completely. Even mangroves, with their enormous root systems, can be stripped away completely. The wildlife at all levels that inhabit these areas are also wiped out.

When cyclonic winds strip vegetation and topple trees, a large pulse of litterfall (fallen leaves, branches, and other natural debris) is generated. This can be as much as 1.4 times the annual litter fall rate. Storm-induced litterfall may contain up to 3 to 5 times more nitrogen, phosphorous, magnesium, and potassium than the average, annual litterfall for an area.

The decomposition of this large amount of organic matter especially that which has fallen into wetlands and/or riverine habitats can lead to low levels of oxygen as this matter decays. This drop in available oxygen may cause the aquatic environment to become hypoxic or anoxic (low or no available oxygen respectively) This then impacts fish and other animals living in the areas.

Cyclones appear to have a significant impact on sea turtle nest survival. Sea turtle nests can be inundated, washed out, or buried by sand brought in with the high tides and increased wave action associated with a tropical system.

Fixed species such as oysters are also significantly impacted by tropical cyclones. Tropical storms detrimentally impact oyster reefs through physical disturbance (waves pounding into the reefs cause breakage), sedimentation, and extreme salinity changes. These effects are typically due to the storm surge, high winds, and high rainfall associated with each storm.

The waves generated by cyclones are larger and more powerful than those experienced under normal conditions. These large waves can significantly impact coral reef systems. Damage to coral reefs can vary from almost total destruction to no effects at all over a distance of just a few meters. The amount of tropical cyclone damage to corals is species-specific because the vulnerability of colonies is a function of their shape, strength of their skeletons and anchor positions, as well as their orientation.

Delicate, branching corals are more vulnerable to wave damage than corals with a boulder-like growth form. Dislodged coral pieces can cause further damage during a cyclone event as they are propelled onto other parts of the reef. Excessive sedimentation reduces available light, inhibiting photosynthesis by the coral’s symbiotic algae. Silt may also settle on the coral surface, blocking feeding and respiration.

The destruction of nesting, roosting and feeding sites can cause the local extinction of a range of organisms from insects and reptiles to birds.

Demoina and Eline.

In South African terms the cyclone that sticks in everyone’s mind is Demoina

Though 28 years ago it is still considered the most devastating tropical cyclone to have struck the south-east coast of Africa in the last century. This changed in 2000 when a level 4 storm, a tropical cyclone Eline, devastated parts of Madagascar, practically crippled Mozambique and impacted heavily on Zimbabwe.

In South Africa and Swaziland, Cyclone Eline caused minimum damage to buildings but torrential rains flooded parts of the north eastern coast. However when we cross the bridges in the southern part of the Kruger National Park we are reminded of the flood levels of the river below in February 2000, the flood line is also indicated on the buildings at Pafuri.

Regular visitors will also remember the devastation in the southern and central parts of the Kruger National Park earlier this year when the tropical storm came and went and nature had healed it's scars and most of the man made objects have by now also been restored.

Cyclone Demoina resulted in the loss of 214 human lives, and the lives of countless livestock and wildlife.

Eight bridges were washed away by the flood-waters in KwaZulu-Natal, including the bridge connecting the town of St Lucia to the mainland.

Major morphological changes occurred at the mouth of Lake St Lucia, where all man-made structures were obliterated, as the two river channels at the mouth were scoured from 2–3 metres to 10–14 metres in depth and widened by up to 300 metres, while the shoreline between the two channels retreated in places up to 100 metres, with an estimated 16,000,000 cubic metres of sediment being removed from the lower reaches of the system. Some 700mm or 28 inches of rain were recorded over 24 hours. The losses were estimated at one hundred million rand, which in those years was a huge amount of money.
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Re: Tropical storms.

Unread post by Yoda »

There is this massive cyclone over the Phillipines at the moment.
They are talking of unconfirmed windpseeds of 235 miles/hour!

We had a big Atlantic storm hit the UK a week ago. The fastest gust recorded was 91 miles/hire
And this storm caused a huge amount of damage.

This one over the Phillipines makes our storm look like a baby!
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