Hydrometeorological Hazards

• Hydrology


  A science that deals with the properties, distribution and circulation of water on and below the earth's surface and in the atmosphere
• Meteorology


  The scientific study of the atmosphere that focuses on weather processes and forecasting
• Weather


  The state of the atmosphere at a particular time and place, described in terms of variable conditions such as temperature, humidity, wind velocity, precipitation and barometric pressure
• Climate


  The average course of weather conditions for a particular location over a period of many years
• Hydrometeorological hazards


  Caused by extreme meteorological and climate events such as floods, droughts, hurricanes, tornadoes, landslides or mudslides
• Cyclone


  An intense low pressure system characterized by strong spiral winds towards the center in a counter-clockwise flow in the Northern hemisphere
• Classification of Cyclone

  • Tropical Depression - maximum winds 35-63 km/h
  • Tropical Storm - maximum winds 64-118 km/h
  • Typhoon - maximum winds exceeding 118 km/h
• Typhoon


  A large, powerful and violent cyclone that is a low pressure area rotating counter clockwise and containing rising warm air that forms over warm water in the Western Pacific Ocean
• Hurricane


  A typhoon formed in the Atlantic ocean
• Cyclone


  A typhoon formed in the Indian Ocean
• Wily-wily


  A typhoon formed in Australia
• Thunderstorm


  A weather condition that produces lightning and thunder, heavy rainfall and possibly a tornado. It is a violent local atmospheric disturbance accompanied by lightning, thunder, heavy rain, often strong gusts of wind, sometimes by hail
• Tornado


  A violently rotating column of air extending from a thunderstorm to the ground, developing from severe thunderstorms in warm, unstable air along and ahead of cold fronts
• Flash Flood


  A rapid flooding of geomorphic low-lying areas like washes, rivers, dry lakes and basins, caused by heavy rain associated with severe thunderstorm, hurricane, tropical storm or melt water from ice or snow
• Flood


  The overflowing of land areas which are not normally covered by water, caused by a temporary rise or the overflowing of a river, stream, or other water course, inundating adjacent lands or floodplains
• Key elements of Flood

  • Rainfall Intensity - the rate of rainfall
  • Rainfall Duration - how long the rain lasts
• Storm Surge


  A rise of seawater above normal sea level on the coast, generated by the action of weather elements such as cyclonic wind and atmospheric pressure
• El Niño & La Niña


  Complex weather patterns resulting from variations in ocean temperatures in the Equatorial Pacific, characterized by fluctuations in temperature between the ocean and atmosphere. La Niña is the cold phase, El Niño is the warm phase
• 5 types of Flood includes flash flood, river flood, coastal flood, urban flood, and ice jam.