Lesson 2.4 - 2.5

• Hydrometeorological hazards


  Processes or phenomena of atmospheric, hydrological or oceanographic nature that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage
• The Philippines is considered very vulnerable to natural hazards and disasters, which include typhoons, earthquakes, floods, volcanic eruptions, landslides, and fires
• The Philippines is located in the Pacific Ring of Fire, where most of the volcanoes in the Philippines are part of
• Continental plate activities around the Pacific Ring of Fire result in volcanic eruptions and tsunamis in the Philippines
• Typhoon or hurricane


  An intense circular storm that originates over warm tropical oceans and is characterized by low atmospheric pressure, high winds, and heavy rain
• Weather forecast


  A scientific estimate of future weather condition, wherein a weather condition is a state of the atmosphere at a given time expressed in terms of the most significant variables
• In the Philippines, cloudiness, rainfall and wind are the weather parameters with significant variation, and therefore of interest to the forecast users
• How is a weather forecast made?

  Weather forecasting is done by a Meteorologist; he/she must know about the existing weather condition over a large area. The accuracy of forecast decision is based on forecasting tools known as the Weather Map.
• Thunderstorm


  • A powerful, short-lived weather disturbance, almost always associated with lightning, thunder, dense clouds, heavy rain or hail, and fast, roaring winds. Thunderstorms occur when layers of dry, moist air rise to cooler regions of the atmosphere in a broad, rapid updraft.
• Thunderstorm stages


  1. Cumulus stage

  2. Mature stage

  3. Dissipating stage
• Flood


  A high-water stage in which water overflows its natural or artificial banks onto normally dry land, such as a river inundating its floodplain
• Inland flooding


  Flooding that occurs in inland areas, hundreds of miles from the coast
• River flooding


  Occurs when water levels in rivers, lakes, and streams rise and overflow onto the surrounding banks, shores, and neighboring land
• Flash floods


  Caused by heavy rain or the sudden release of water over a short period of time. The name "flash" refers to their fast occurrence and also to their raging torrents of water that move with great speed
• Coastal flooding


  The inundation of land areas along the coast by seawater
• Urban flooding


  Occurs when there is a lack of drainage in an urban (city) area
• Storm surge


  The irregular sea-level rise during a tropical cyclone or "bagyo" where powerful winds force the ocean water over the coastal low-lying areas, which can lead to flooding
• For storm surge prone communities, the most important considerations are the strength of the tropical cyclone, the height of the surge, and the community located in the low-lying area
• El Niño


  A large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperatures across the central and east-central equatorial Pacific
• La Niña


  A counterpart to El Niño, which describes the cooling of surface ocean waters in the equatorial region of the Pacific Ocean
• El Niño


  Causes a significant increase in ocean temperature and it occurs at irregular intervals ranging from 2-7 years
• El Niño


  Causes a lack of rain, which is a significant condition experienced in the Philippines
• La Niña


  Causes below-average sea surface temperatures across the east-central equatorial Pacific, with global climate impacts tending to be opposite those of El Niño
• El Niño


  Affects health conditions by causing diseases related to water scarcity or shortage like diarrhea and skin diseases
• La Niña


  Affects health conditions by causing diseases related to wading in floodwaters contaminated with urine of infected animals, such as leptospirosis, and diseases brought by mosquitoes, such as dengue and malaria
• Climate and weather-related hazards, such as typhoons and droughts, as well as earthquakes, volcanic eruptions and tsunamis, are natural hazards, while deforestation, mining and climate change are man-made hazards
• Hazard maps highlight areas that are affected and/or vulnerable to a particular hazard and help prevent serious damage and deaths
• Rainfall distribution throughout the Philippines varies from one region to another, depending upon the direction of the winds and the location of mountain systems
• The Nationwide Operational Assessment of Hazards (NOAH) program under the Department of Science and Technology (DOST) advances the use of cutting edge technology and recommends innovative information services in government's disaster prevention and mitigation efforts
• According to the PAGASA infographic issued on July 7, 2020, a weather phenomenon is expected to arrive in the next few months
• nas Climate Classification shows the monthly rainfall variations in the Philippines: Rainfall distribution throughout the country varies from one region to another, depending upon the direction of the winds and the location of mountain systems.
• Nationwide Operational Assessment of Hazards or NOAH, a program under the Department of Science and Technology (DOST), advance the use of cutting edge technology and recommend innovative information services in government's disaster prevention and mitigation efforts. DOST- NOAH can be accessed online at http://noah.up.edu.ph/.
• Below is a screen shot from the Project NOAH web page, indicating the flood prone areas of Manila. Note the meaning of the colors indicated on the left of the screen shot.
• What weather phenomenon is expected to arrive in the next few months?
• Hydrometeorological hazards are hazards caused by extreme meteorological and climate events which can lead to loss of life, injury or other health impacts, property damage, loss of livelihood, social and economic disruption or environmental damage.
• Examples of hydrometeorological hazards in the Philippines


  • cyclones
  • typhoons
  • flashfloods
  • storm surge
  • lightning storms/ thunderstorms
  • El Niño
  • La Niña
• The government agency which is tasked to monitor and give forecasts and warnings about atmospheric conditions is PAGASA, or Philippine Atmospheric, Geophysical and Astronomical Services Administration.
• Unlike an earthquake, forecasts pertaining to hydrometeorological hazards are easier to predict with the help of some important tools which can monitor atmospheric conditions.
• Thermometer


  Measures the extent of a given substance's hotness or coldness. Mercury is one of the liquids which is overly sensitive to temperature changes. The mercury expands and rises in the capillary tube when the substance to be measured is warm. Instead, mercury contracts. That is, principle of thermal expansion.
• Thermograph


  Records air temperature continuously on graphing paper during a period in a given area. It uses digital infrared imaging to record slight changes in temperature.