Hydrometeorologic

• Hydrometeorological hazards


  Processes or phenomena of atmospheric, hydrological or oceanographic nature that may cause loss of life, injury or other health impacts, property damages, loss of livelihoods and services, social and economic disruptions, or even environmental damages
• Hydrometeorological hazards


  • Tropical cyclones (also known as typhoons and hurricanes)
  • Thunderstorms
  • Hailstorms
  • Tornadoes
  • Blizzards
  • Heavy snowfall
  • Avalanches
  • Storm surges
  • Floods including flash floods
  • Drought
  • Heat waves
  • Cold spells
• Hydrometeorological conditions can be a factor in other hazards such as landslides, wildfires, locust plagues, epidemics, and volcanic eruptions
• Cyclone


  An intense low pressure system which is characterized by strong spiral winds towards the center, called the "Eye" in a counter-clockwise flow in the northern atmosphere. Hazards due to the tropical cyclones are strong winds with heavy rainfall that can cause widespread flooding/flash floods, storm surges, landslides, and mudflow.
• Classification of Cyclone


  • Tropical Depression: maximum winds from 35 kms per hour to 63 kph
  • Tropical Storms: maximum winds of 64 kph to 118 kph
  • Typhoon: maximum winds exceeding 118 kph
• Thunderstorm


  A weather condition that produces lightning and thunder, heavy rainfall from cumulonimbus clouds and possibly a tornado. It is a violent local atmospheric disturbance accompanied by lightning, thunder, and heavy rain, and often by strong gusts of wind, and sometimes by hail. The typical thunderstorm caused by convection occurs when the sun's warmth has heated a large body of moist air near the ground. This air rises and is cooled by expansion. The cooling condenses the water vapor present in the air, forming a cumulus cloud. The turbulent air current within the cloud causes a continual breaking up and reuniting of the rain drops, which may form hail, and build up strong electrical charges that results in lightning.
• Tornado


  A violently rotating column of air extending from a thunderstorm to the ground. Tornadoes come in many size but are typically in the form of a visible condensation funnel which is narrow and touches the earth and often encircled by a cloud of debris. It can have a wide range of colors depending on the environment. Typically, tornados may appear nearly transparent and invisible until dust and debris are picked up.
• Flash Floods


  A rapid flooding of geomorphic low-flying areas like washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, tropical storm, or melt water from ice or snow flowing over ice sheets or snowfields. Flash floods may occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam. Flash floods are distinguished from regular floods by a timescale of less than six hours. The water that is temporarily available is often used by foliage with rapid germination and short growth cycles, and by specially adapted animal life.
• Storm Surges


  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. Sea level is raised and driven towards the coast. Where the depth is shallow and the slope of the sea bed is gradual, the natural flow of the water is delayed by the effect of friction on the sea bed. As more water moves from the sea to the coast excess water piles up on the shore line. This piling up of water makes a large volume of water which might eventually flow into the hinterland some distance from the coast. Depending upon the shape of the coastline and the slope of the sea bed, storm surges can sweep across large portion of coastal areas.
• El Nino and La Nina


  Complex weather patterns resulting from variation in ocean temperatures in the Equatorial Pacific. These two phenomena are opposite phases of what is known as the El Nino-Southern Oscillation (ENSO) cycle. La Nina is sometimes referred to as the cold phase of ENSO and El Nino as the warm phase of ENSO. These deviations from normal surface temperature can have large-scale impacts not only on ocean processes, but also on global weather and climate.
• El Nino and La Nina episodes typically last nine to 12 months, but some prolonged events may last for years. While their frequency can be quite irregular, El Nino and La Nina events occur on average every two to seven years. Typically El Nino occurs more frequently than La Nina
• Preparedness and Mitigation for Hydrometeorological Hazards

  • Typhoon
  • Thunderstorm
  • Tornado
  • Storm Surge
• Typhoon Preparedness (What to do before)

  1. Establish and maintain coordination with Barangay Disaster Coordinating Councils (BDCC) and personnel

  2. Ensure that the house can withstand heavy rain and strong winds. House built at ground level may be anchored by guy wires to strengthen the stability of the structure

  3. Learn more about typhoon and other weather disturbances, their signs and warnings, effects and dangers and how to protect house and other properties

  4. Learn something relevant to mitigation and preparedness for tropical cyclones

  5. Participate actively in the school's disaster response - drill or simulation
• Typhoon Response (What to do during)

  1. Monitor through radio or other reliable sources the latest official report of PAGASA on the typhoon

  2. When a house is no longer safe, evacuate immediately to safer places like evacuation centers or houses of relatives that are proven stable and can withstand strong wind and rain

  3. Stay indoors and away from windows

  4. Keep an open line of communication with relatives that are not affected to keep them posted

  5. Ensure that members of the family will remain calm by keeping them informed of the latest developments
• Thunderstorm Preparedness (What to do)


  1. Develop a Family Preparedness Plan

  2. Learn more about your area's severe thunderstorm risk

  3. Discuss how you would know if a thunderstorm may produce a tornado

  4. Recommend trimming and removal of dead or rotting trees that could fall and may cause damage or injury

  5. Secure outdoor objects that could be blown away and cause damage

  6. Secure house doors and windows both from the inside and outside

  7. Learn how to estimate the distance of the thunderclouds, by computing the difference in time (second) between seeing the fast of lightning and hearing the claps of thunder. (1 second = 1000 ft.)
• Thunderstorm Response (What to do during)

  1. Learn to do the lightning safety position and stay away from structures, trees, towers, fences, telephone lines, or power lines if out in the open

  2. Carefully watch out for falling debris and flash floods

  3. Stay calm throughout the occurrence of thunderstorms

  4. Postpone all outdoor activities

  5. Avoid plumbing and bathroom fixtures that are good conductors of electricity

  6. Unplug or turn off all appliances and other electrical items such as computers. Electric power surges and storm lightning can cause serious damage to these appliances

  7. Turn off the air conditioner and television, and stay off the phone until the storm is over. Use a battery operated radio for gaining information

  8. Choose and move to a "safe place" in your house (if there is any) where members of the family can gather together during a thunderstorm preferably on the lowest floor of your house. This should be a place where there are no windows, skylights, or glass doors, which could be broken by strong winds or hail, causing damage or injury
• Lightning Safety Position


  By placing your heels together and hands over your ears, you become a smaller target for lightning. This positioning helps direct the electrical current away from vital organs, potentially saving your life.
• Tornado Preparedness (What to do before)

  1. Develop a preparedness plan for the whole family

  2. Have periodic drills with the members of the family

  3. Inspect pre-designated areas to ensure the best protection

  4. Keep an open line of communication with other members of the family

  5. Listen to radio and television for information

  6. Store flashlights and back-up batteries to receive warnings
• Tornado Response (What to do during)

  1. Move to a pre-designated area or an interior room on the lowest floor and get under a sturdy piece of furniture

  2. Stay away from windows

  3. Lie flat in a dépression if caught outside your house/school or any building
• Tornado Rehabilitation (What to do after)

  1. Report broken utility lines (electricity, water, gas, etc.) immediately to appropriate agencies/authorities

  2. Ensure that electrical appliances are checked by a competent electrician before switching them on

  3. Avoid affected areas

  4. Continue to listen to a radio or local television stations and return home only when authorities indicate it is safe to do so

  5. Stay away from any building that is still flooded
• Storm Surge Preparedness (What to do before)

  1. Know the storm surge risk zones and identify safer grounds for relocation if necessary

  2. Stay off the beach when weather disturbance exists

  3. Ensure that everyone is familiar with the identified escape routes of the family to higher grounds

  4. Help establish evacuation plans and procedures

  5. Participate in the regular conduct of drills and exercises
• Storm Surge Response (What to do during)

  1. Immediately move to higher grounds upon detection of signs of a probable storm surge or upon receiving a warning that a storm surge is imminent

  2. Be alert of and stay away from steep, high coastal areas which are prone to landslides

  3. Switch off power supply

  4. Stay on the inland side away from the potential flow of water

  5. If caught in a storm surge, take hold, of large boulders or tree trunks which can provide protection from the force of water or debris carried by the flowing water
• Storm Surge Rehabilitation (What to do after)

  1. Do not eat fresh food that came in contact with flood waters

  2. Drinking water should be submitted to proper authorities for testing

  3. Check damage of the house to ensure that there is no danger of collapse

  4. Check the house for electrical damage and open live wires. Electrical fixtures should only be switched on after making sure that it is safe to do so

  5. Help clean all mud and debris immediately