facts about...

Natural hazards

• There were about 8 400 disasters from 1980 to 2007 caused by natural hazards around the world, affecting over 2 million people. Of this, 90 per cent of the disasters and 70 per cent of casualties were caused by weather-, climate- or water-related hazards .
  
  
• El Niño happens when the temperature of the normally cool surface water of the ocean increases during a few months.
  
  
• More than 900 million people are affected by desertification and drought.
  
  
• With climate change, there could be more droughts in the future, thereby increasing the risk of desertification in some parts of the world.
  
  
• “Hurricane”, “tropical cyclone,” “very severe cyclonic storm” and “typhoon” are different terms for different regions for the same phenomenon. They are weather phenomena accompanied by torrential rain and sustained wind speeds of more than 119 kilometres per hour:
  - In the western North Atlantic, central and eastern North Pacific, Caribbean Sea and Gulf of Mexico, this weather phenomenon is called a “hurricane”
  - In the western North Pacific, it is called a “typhoon”
  - In the Bay of Bengal and Arabian Sea, it is called a “very severe cyclonic storm”
  - In the western South Pacific and south-east Indian Ocean, it is called a “severe tropical cyclone”
  - In the south-west Indian Ocean, it is called a “tropical cyclone”
  
  
• Hurricanes are classified into five categories sustained wind speeds of:
  Category 1 – 119-152 km/h*
  Category 2 – 153-177 km/h
  Category 3 – 178-209 km/h
  Category 4 – 210-249 km/h
  Category 5 – over 249 km/h
  *kilometres per hour
  
  
• Meteorologists use modern technology such as satellites, weather radars and computers to track tropical cyclones as they develop.
  
  
• The strongest gust of wind ever recorded was measured around the eye of Tropical Cyclone Olivia in 1996 at Barrow Island, Australia, with maximum sustained wind speeds of 408 kilometres per hour!

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