DRRR HYDROMET

• Hydrometeorological hazards


  • Dealing with the phenomena on and below the earth's surface and in the atmosphere
  • Deals with the water and its phenomena and with climate
  • Study of the water cycle with emphasis on the interrelationship between them
  • Deals with the water and the atmosphere
• Hydrometeorological hazards


  • Typhoon
  • Thunderstorm
  • Flood & Flash Floods
  • Storm Surge
  • El Nino & La Nina
• Typhoon


  A rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters and has a closed low-level circulation

  
• Formation of a Typhoon


  1. Presence of warm ocean temperature of 80°F (26.67°C) depth: 150 ft

  2. Presence of the Coriolis effect

  3. Presence of low or weak vertical wind shear in the atmosphere

  4. Increased chances of a typhoon developing within 24 – 48 hrs

  
• When typhoon weakens


  Tendency to stall / dissipate and weaken

  
• When typhoon encounters unfavorable environment

  Typhoon weakens and dissipates

  
• When they make landfall


  Typhoons weaken when they are over land

  
• Typhoons occur all year round regularly though there is a distinct minimum in February and the first half of March. The main season goes from July to November with a peak in late August/early September.

  
• Public Storm Warning Signal (PSWS)

  • When any tropical cyclone is expected for the first time, the PSWS #1 is raised over the locality
  • The PSWS indicates the range of the wind speeds expected in at least 36 hours when PSWS #1 is put in effect initially; in at least 24 hours with PSWS #2; in at least 18 hours with PSWS #3, in at least 12 hours with PSWS #4; and in at least 12 hours with PSWS #5
  • The PSWS may be upgraded or downgraded in the subsequent issues of the warning bulletin when the signal number remains in effect

  
• The delineation of areas for a given PSWS is based on the forecast track of the tropical storm or typhoon at the time of issue of the warning bulletin. The intensity of the tropical cyclone also determines the PSWS over a given locality.

  
• Monsoons


  • Southwest monsoon (HABAGAT)
  • Northeast monsoon (AMIHAN)
• Formation of Thunderstorms


  1. Warm air rises and transfers the heat from the Earth's surface to the upper levels of the atmosphere

  2. The water vapor that it carries begins to cool, releases the heat & eventually condenses into clouds

  3. Liquid drops freeze as the storm cloud rises into the freezing air

  4. The ice crystals collide with each other and grow a little bit more ice from the other

  5. The electrical charge builds up and lightning (sounds called thunder) is produced

  6. Cumulus/Developing Stage: strong updrafts act to build the storm

  7. Mature Stage: marked by heavy precipitation and cool downdrafts

  8. Dissipating Stage: when the warm updrafts disappear completely, precipitation becomes light and the cloud begins to evaporate
• Floods and flash floods are caused by excessive rainfall, dam/levee failure, or sudden release of water by an ice jam.
• Floods and flash floods

  Brought about by excessive rainfall or sudden release of water, which can become dangerous and life-threatening in just a short period of time
• Floods in watersheds


  Can be powerful enough to destroy bridges, roads, and other infrastructure
• Storm Surge


  A coastal flood or exceptionally high tide caused by a storm, particularly by its strong winds, low pressure, and associated waves

  
• Storm surge


  Caused by the low pressure at the eye of the storm, which leads to its accumulation and abnormal rise in sea level

  
• Storm surge


  Can be amplified by the shape and height of the wave, and can cause extensive damage and loss of life

  
• Numerous incidences of destroyed property and loss of lives at different seashores of the country have already been recorded due to storm surges.
• El Niño and La Niña


  Abnormal weather patterns caused by the fluctuations in ocean temperatures
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