Tropical Cyclones

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Tropical Cyclones
This presentation is to be viewed with the
storyboard (see Module 3 Activity 1 on the CD).
It demonstrates how planning can result in a
presentation that answers the unit question. You
can delete this text box.

• Are we at risk?

http//earthobservatory.nasa.gov/Newsroom/NewImage
s/Images/seawifs_cyclone_dera.jpg
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Questions

• What is a tropical cyclone?
• How does it threaten us?
• What parts of South Africa are threatened?
• How can we minimise the risk?

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What is a Tropical Cyclone?

• relatively small, intensely developed low
  pressure cell
• occur over warm oceans
• diameter can range between 200 and 2000 km
• maximum wind speed exceeds 110 km/h
• Torrential rain

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How does it threaten us?

• Floods
• Damage to roads, bridges, buildings
• Loss of farmland
• Silting of dams and river flood plains

http//www.whistler.com/buzzard/photoj5.html
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How does it threaten us?

• Wind damage
• Loss of crops
• Damage to buildings and communications
• Stormy seas

http//coastalhazards.wcu.edu/StormDamage/Opal/opa
l1.jpg
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What parts of SA are threatened?

• Where do they come from?
• How do they travel?

http//www.weathersa.co.za/wfacts/9902-3.GIF
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Conclusion most storms miss us

• Few reach 25 S as mature storms
• Few reach 50

http//www.dmc.co.zw/images/saison_cyc_2001_2002.g
if
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Past events in South Africa
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Demoina and Imboa (1984)

• Extensive flood damage in KZN

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Eline (Feb 2000)

• Extensive flooding in Mozambique and Limpopo
  valley

http//news.bbc.co.uk/1/hi/world/africa/649873.stm
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Hudah (2002)

• Serious floods in Mozambique

http//www.reliefweb.int/mapc/afr_sth/cnt/moz/moz_
hudah.html
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Japhet (2003)

• Flood disaster in Mozambique and Zimbabwe

http//www.reliefweb.int/w/rwb.nsf/ (2003)
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How can we minimise risk?

• Monitor information from the weather bureau
• Look at weather satellite images
• Avoid settling on northern coastal shores
• Dont live on river banks in KwaZulu Natal

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Conclusion

• We are not at high risk in this country
• But we should have flood relief programmes in
  place in KwaZulu Natal