dr&rr

• Hydrometeorological hazards


  • Typhoons
  • Storm Surge
  • Thunderstorms
  • Flooding
  • El Niño and La Niña

  
• Hydrometeorological hazards


  Involve the interaction of the atmosphere, bodies of water, and land, which pose a threat to lives and human properties
• Hydrometeorological events occur more frequently and sometimes have even more far-reaching adverse effects on the economy, the environment, and society than to any other type of natural disaster
• Typhoon


  A severe meteorological disturbance with high winds and heavy rains, which revolve around a central low-pressure area. In the Pacific Ocean's northern corner, it is the most powerful type of tropical cyclone

  
• Types of tropical cyclones

  • Tropical Depression - wind speed up to 62kph
  • Tropical Storm - wind 63-118kph
  • Typhoon - wind speed greater than 118kph
  • Super Typhoon - wind exceeding 220kph

  
• Effects of tropical cyclones

  • Strong Wind
  • Storm Surge
  • Heavy Rain

  
• Storm Surge


  A localized unusual increase of seawater level way above the predicted astronomical tide level

  
• Factors influencing storm surge

  • Storm Intensity (Wind Speed)
  • The Pressure Effect
  • Size
  • Storm Forward Speed
  • The Angle of Approach to Coast
  • The Effect of the Earth's Rotation
  • The Rainfall Effect
  • The Geometry of the Coastal area (Bathymetry, Topography, Coastline Shape and Local Features)
  • Timing

  
• Buildings, roads, bridges, piers, and other infrastructures may not only be submerged but also they can be washed away and destroyed when a storm surge hits an area if they are not firmly rooted in the ground

  
• Thunderstorm


  A violent, transient type of weather disturbance associated with thousands of meters tall cumulonimbus clouds and which usually involves lightning and thunder, strong winds, intense rainfall, and occasionally tornadoes and hail

  
• Thunderstorm life cycle


  1. Developing or cumulus stage

  2. Mature Stage

  3. Final or Dissipating Stage

  
• The occurrence of thunderstorms poses a danger to people and properties. Many people are injured or die in spite of warnings because they are unaware of the preparedness and safety measures and probably even lack understanding of the phenomenon itself

  
• Effects of lightning strike on humans

  • Direct harm through contact with lightning channel or branches
  • Blunt force trauma or hearing damage
  • Secondary effects like explosions and fires

  
• Flooding


  The unusual rise of water level in the coastal areas, plains, rivers, and in highly urbanized area which may be a result of natural phenomena, human activities, or both

  
• Destructive effects of flooding

  • Primary Effects - direct interaction of humans and their properties with floodwaters
  • Secondary Effects - short-term indirect consequences
  • Tertiary Effects - long-term indirect consequences
• Flood control structures


  • Dams
  • Diversion Canals
• Things to do before, during, and after a flood

  • Before - Find out flood prone areas, prepare emergency kit
  • Before - Keep tuned to weather updates, inform household, move valuables
  • During - Avoid walking/driving through floodwaters, turn off utilities
  • After - Take precautions, document damage
• El Niño


  A natural climatic phenomenon characterized mainly by the cyclic fluctuation of warm and cold sea temperatures and atmospheric pressure in the eastern equatorial pacific
• Causes of El Niño

  Wind is usually blown to the west along the equator in the Pacific region, which causes the piling or water that can reach up to half a meter in the western Pacific. In the eastern portion of the Pacific, deeper, upwelled, and colder water replaces the insulated surfaces water that has been pushed west.
• Effects of El Niño

  An area that has been receiving below average amount of rainfall for a period of three months is considered under a dry spell, while an area receiving below average amount of rainfall for a period of five months is already experiencing a drought
• La Niña


  The exact opposite of El Niño, involving prolonged unusual cooling (of at least 0.5°C) of sea surface temperatures in the central and eastern equatorial Pacific that may last 1-3years
• Causes of La Niña

  A strengthening of the easterly trade winds, which blow more warm water toward the west and allow the upwelling of cold water in the east
• Effects of La Niña in the Philippines

  Near normal to above rainfall conditions, particularly over the eastern sector of the country. Increase in the number of tropical cyclones that enters the Philippines Area of Responsibility (PAR)