Tropical Cyclones Are we at risk http earthobservatory

Tropical Cyclones Are we at risk? http: //earthobservatory. nasa. gov/Newsroom/New. Images/seawifs_cyclone_dera. jpg

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

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

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/photoj 5. html

How does it threaten us? • Wind damage – Loss of crops – Damage to buildings and communications – Stormy seas http: //coastalhazards. wcu. edu/Storm. Damage/Opal/opal 1. jpg

What parts of SA are threatened? • Where do they come • from? How do they travel? http: //www. weathersa. co. za/wfacts/9902 -3. GIF

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. gif

Past events in South Africa

Demoina and Imboa (1984) – Extensive flood damage in KZN

Eline (Feb 2000) • Extensive flooding in Mozambique and Limpopo valley http: //news. bbc. co. uk/1/hi/world/africa/649873. stm

Hudah (2002) • Serious floods in Mozambique http: //www. reliefweb. int/mapc/afr_sth/cnt/moz_hudah. html

Japhet (2003) – Flood disaster in Mozambique and Zimbabwe http: //www. reliefweb. int/w/rwb. nsf/ (2003)

How can we minimise risk? • Monitor information from the weather bureau • Look at weather satellite images • Avoid settling on northern coastal shores • Don’t live on river banks in Kwa. Zulu Natal

Conclusion • We are not at high risk in this country • But we should have flood relief programmes in place in Kwa. Zulu Natal