typhoons

• Ingredients in tropical cyclone formation:

  • Deep ocean water
  • Warm sea temperature
  • Coriolis Force
• Why do tropical cyclones form?

  Redistribution of heat through wind from the equatorial regions to polar regions
• Storm Surges - Localized unusual increase of sea water level beyond the predicted astronomical tide level primarily due to intense winds and lowered atmospheric pressure.
• Flood Types

  • Riverine
  • Estuarine & Coastal
  • Urban flooding
  • Catastrophic
  • Flash flood
• Riverine

  • Increase in river water levels
  • Extreme and sustained rainfall
• Large River - slow rising
• Small river - fast rising
• Estuarine & Coastal

  • Storm surges
  • Unusually high tides
• Urban flooding

  • Large areas of impermeable surfaces
  • Man-made causes
• Catastrophic

  • Ground failure, liquefaction, landslides that may be triggered by natural disasters.
  • Breakage of dams
• Flash flood

  • Rapid & short-lived
  • Due to intense rainfall / collapse of dam
• ENSO - El Niño Southern Oscillation
• ENSO - Cyclic fluctuation of warm and cold sea surface temperatures and atmospheric pressure in the central and eastern equatorial pacific.
• ENSO - causes extreme regional-scale weather and climate pattern changes.
• ENSO - most powerful climatic force on earth
• El Niño - Warm Phase
• La Niña - Cold Phase
• El Niño - lasts for 9 months to 2 years, starts between december to February occurs every 2-9 years
• La Niña - Lasts 1-3 years
• La nina - occur alternatingly and usually recur every 3-5 years or 2-7 years