Tropical CyclonesTropical CyclonesAre we at risk?Are we at risk?

http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/seawifs_cyclone_dera.jpg

QuestionsQuestions

• What is a tropical cyclone?What is a tropical cyclone?

• How does it threaten us?How does it threaten us?

• What parts of South Africa are What parts of South Africa are threatened?threatened?

• How can we minimise the risk?How can we minimise the risk?

What is a Tropical Cyclone?What is a Tropical Cyclone?

• relatively small, intensely developed relatively small, intensely developed low pressure celllow pressure cell

• occur over warm oceansoccur over warm oceans

• diameter can range between 200 and diameter can range between 200 and 2000 km 2000 km

• maximum wind speed exceeds 110 maximum wind speed exceeds 110 km/hkm/h

• Torrential rainTorrential rain

How does it threaten us?How does it threaten us?

• FloodsFloods– Damage to roads, Damage to roads,

bridges, buildingsbridges, buildings– Loss of farmlandLoss of farmland– Silting of dams and Silting of dams and

river flood plainsriver flood plains

http://www.whistler.com/buzzard/photoj5.html

How does it threaten us?How does it threaten us?

• Wind damageWind damage– Loss of cropsLoss of crops– Damage to Damage to

buildings and buildings and communicationscommunications

– Stormy seasStormy seas

http://coastalhazards.wcu.edu/StormDamage/Opal/opal1.jpg

What parts of SA are What parts of SA are threatened?threatened?

• Where do they Where do they come from?come from?

• How do they How do they travel?travel?

http://www.weathersa.co.za/wfacts/9902-3.GIF

Conclusion – most storms miss Conclusion – most storms miss usus• Few reach 25 S as mature stormsFew reach 25 S as mature storms

• Few reach 50 Few reach 50

http://www.dmc.co.zw/images/saison_cyc_2001_2002.gif

Past events in South AfricaPast events in South Africa

Demoina and Imboa (1984)Demoina and Imboa (1984)

– Extensive flood Extensive flood damage in KZNdamage in KZN

Eline (Feb 2000)Eline (Feb 2000)

• Extensive flooding in Mozambique Extensive flooding in Mozambique and Limpopo valleyand Limpopo valley

http://news.bbc.co.uk/1/hi/world/africa/649873.stm

Hudah (2002)Hudah (2002)

• Serious floods in MozambiqueSerious floods in Mozambique

http://www.reliefweb.int/mapc/afr_sth/cnt/moz/moz_hudah.html

Japhet (2003)Japhet (2003)

– Flood disaster in Mozambique and Flood disaster in Mozambique and ZimbabweZimbabwe

http://www.reliefweb.int/w/rwb.nsf/ (2003)

How can we minimise risk?How can we minimise risk?

• Monitor information from the Monitor information from the weather bureauweather bureau

• Look at weather satellite imagesLook at weather satellite images

• Avoid settling on northern coastal Avoid settling on northern coastal shoresshores

• Don’t live on river banks in KwaZulu Don’t live on river banks in KwaZulu NatalNatal

ConclusionConclusion

• We are not at high risk in this We are not at high risk in this countrycountry

• But we should have flood relief But we should have flood relief programmes in place in KwaZulu programmes in place in KwaZulu NatalNatal