hydrometeorological hazards

• HYDROMETEOROLOGICAL HAZARD

  Process or phenomenon 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.
• El Nino

  Associated with warming the central and eastern tropical Pacific, while La Nina is the reverse, with a sustained cooling of these areas. These changes in the Pacific Ocean occur in a cycle known as the El Nino-Southern Oscillation (ENSO).
• ENSO

  During ENSO, ocean temperatures become warmer or cooler than usual at different locations.
• La Niña

  According to NASA, it is the "build up of cool waters in the equatorial Eastern Pacific." Its effects are opposite to El Niño. Frequently, La Niña follows after El Niño. It usually brings heavy rains that trigger floods and landslides, but it can also bring in benefits to the country such as the possibility to grow crops in mountainous areas and those areas that are unreachable by irrigation.
• WHAT IS ENSO?

  global climate phenomenon that emerges from variations in winds and sea surface temperatures over the tropical Pacific Ocean. Those variations have an irregular pattern but do have some semblance of cycles.
• Tropical cyclone

  An intense low pressure system with a minimum sustained wind velocity of 35 kilometers per hour. The tropical cyclone has an eye which is 10 to 100 kilometers in diameter. There is an EYE WALL where the precipitation is heaviest and the wind is strongest. Spiral rain bands surround the eye
• Categories of tropical cycloes by speed of maximum sustained winds

  • Tropical Depression: up to 61 kilometers per hour (kph)
  • Torpical Storm: 62 to 88 kph
  • Sever Tropical Storm: 89 to 117 kph
  • Typhoon: 118 to 220 kph
  • Super Typhoon: More than 220 kph
• The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) is the official source of information about tropical cyclones even before it enters The PAR. Tropical cyclones are classified into five,according to their strength or the speed of the maximum winds near the center.
• Public Storm Warning Signals

  • Signal 1: No Classes in Kindergarten
  • Signal 2: No Classes in Kindergarten, Elementary, and High School
  • Signal 3: No Classes in ALL LEVELS including tertiary level
• The signals also indicates which classes are to suspended autotomaticby the department od Education. however local goment units or school auththies can suspend classes when the local situation warrants it.
• Floods


  It usually affects low-lying and coastal areas. This is due to the overflowing of water from lakes, streams, and other bodies of water. The accumulation of rainwater in drainages also causes floods, particularly in urban areas. The natural causes include intense or prolonged rainfall, storm surge, and high tide.
• Man-made causes of floods

  • Increased urbanization and coastal development
  • Informal settlers
  • Indiscriminate dumping of garbage
  • Deforestation
  • Failure of levees and dams
  • Blasting
• Types of floods

  • River flood: caused by the overflowing of rivers when the run-off exceeds the capacity of the channels
  • Flash flood: caused by a very short period of unusually heavy rainfall
  • Coastal flood: occurs when strong onshore winds push the water inland
• PAGASA has color-coded warning signals that indicate the appropriate response to aspecific level of flooding.
• How to prepare for flooding (Before Flooding)

  • Know the frequency and intensity of location in your area.
  • Be familiar with the flood warning system in your community.
  • Keep informed of daily weather conditions.
  • Designate an evacuation area for the family and livestock and assign family members specific instructions and responsibilities according to an evacuation plan.
  • Keep stock of food that requires little cooking and refrigeration as electric power'may be interrupted.
  • Keep a transistorized radio and flashlight with spare batteries, emergency cookingequipment, candles, matches, and handy first-aid kit in case of emergency.
  • Securely anchor weak dwellings and items.
• How to prepare for flooding (When Warned of Flood)

  • Be alert to the possibility of flood if it has been raining for several days. Flood happens as the ground becomes saturated.
  • Listen to the radio for emergency instructions.
  • If advised to evacuate, do so. Do not panic. Move to a safe area before access is cut off by flood waters.
  • Store drinking water in containers, as water service may be interrupted.
  • Move household belongings to upper levels.
  • Bring livestock to higher ground.
  • Tum off electricity at the main switch in the building before evacuating and also lock your house.
• How to prepare for flooding (During Flooding)

  • Avoid flooded areas.
  • Do not attempt to cross rivers or flowing streams where water is above the knee.
  • Beware of water-covered roads and bridges.
  • Avoid unnecessary exposure to the elements.
  • Do not go swimming or boating in swollen rivers.
  • Eat only well-cooked food. Protect leftovers against contamination.
  • Drink clean or preferably boiled water only.
• How to prepare for flooding (After Flooding)

  • Reenter the dwellings with caution when using a flashlight, lantern, or torch.'There may be flammable materials inside.
  • 2 Beware of fire hazards like broken electric wires.
  • Do not eat food and drink water until they have been checked for food and water contamination.
  • Report broken utility lines (electricity, water, gas, and telephone) to appropriate agencies or authorities.
  • Do not turn on the main switch or use appliances and other equipment until they have been checked by a competent electrician.
  • Consult health authorities for immunization requirements.
  • Do not go "sightseeing" in disaster areas. Your presence might hamper rescue and other emergency operations.
• Storm surge


  A sudden rise of sea level above the normal level on the coast due to a drop in the atmospheric pressure and the force of the wind as a tropical cyclone approaches the coast.
• Causes of storm surge

  • Wind/pressure effect: The stronger the wind of the tropical cyclone and the lower the atmospheric pressure, the higher the storm surge.
  • Rainfall effect: Heavy rains associated with an intense tropical cyclone add to the total sea level near the coast.
  • Tidal effect: If surge coincides with the occurrence of high tide, water level will be higher than when it occurs during low tide condition.
  • Shape of the coastline and slope of the sea bed: The shallower the slope, the higher the surge to the coastal communities.
• How to prepare for a storm surge

  • Make plans for evacuating the member of your family and yourself to higher ground before a storm surge happens.
  • Stay off the beach when a weather disturbance is approaching or happening in your coastal community.
  • Refrain from building houses within 500 meters from flat or gently slopig coastlines.
  • During weather disturbance, rely on your initiative rather than wait for government action
  • Ensure systematic safe keeping of valuables.
  • Evacuate to higher ground away from beaches as soon as possible when a storm or typhoon approaches you coastal community.
• Thunderstorm


  A localized storm cloud that produces lightning and thunder, and often brings heavy rain shower or hail as well as strong gusty winds. The typical thunderstorm is five kilometers in diameter and lasts an average of thirty minutes, although some may last longer.
• Three stages of a Thunderstorm

  • Cumulus Stage: As the sun heats the Earth's surface, the ground warms the air above it. The warm air rises and water vapor condenses to cumulus clouds.
  • Mature Stage: The cloud causes heavy precipitation , severe lightning, strong and gusty winds, hail, and tornadoes at times. It is at this stage that the thunderstorm is the storngest.
  • Dissipating Stage: The precipitation decreases its intensity and clouds begin to dissipate
• Dangerous weather conditions produced by a Thunderstorm

  • Heavy rains, floods, tornadoes, hailstones, and lightning
• Hailstones


  Ice crystals falling from a thunderstorm
• Lightning


  The most dangerous hazard associated with thunderstorm, is a visible electrical discharge due to high voltage differences that build up within the clouds, between the clouds, and the ground. The sudden lightning makes sound waves that we hear as thunder. Lightning can cause deaths and injuries and can spark fires.
• Signs of an impending thunderstorm

  • Towering Cumulonimbus clouds
  • Darkening skies
  • Flashes of lightning and gusty winds
  • Sound of Thunder
  • Static on your communication equipment
• How to prepare for a thunderstorm


  • Stay or go indoors.
  • Stay away from anything that could conduct electricity.
  • Do not use any plug-in electrical appliances.
  • Do not use the telephone/ cellular phone during the occurence of thunderform.
  • Stay in your automobile if you are travelling.
  • Do not use metal objects outside the house or building.
  • Stay away from bodies of water.
  • If you are outdoors, seek shelter from lightning.
  • If you cannot find shelter, avoid the solitary tree or the tallest object in the area. Lightning tends to strike tall objects.
  • 10. Become a very small target! Squat on the ground. Drop to your knees and bend your hands forward over your knees.
  • 11. When you feel an electrical charge if your hair stands on end or your skin tingles— lightning may be about to strike you. Drop to the ground immediately.
• Tornado


  A localized windstorm characterized by a visible funnel-shaped, rapidly whirling cloud extending downward from the base of a dark cumulonimbus cloud. It is also known as twister. It acts like a vacuum cleaner, sucking and carrying aloft objects along its path such as trees, structures, or debris.
• Precursory Signs of a Tornado

  • A dark, often greenish sky, large hail, a low-lying rotating cloud called a wall cloud, a loud roar similar to a freight train, and a sudden change in wind direction or speed.
• What to do during a tornado

  • When indoors, keep calm; stay under an interior hallway, at the lowest place in a building, or under sturdy furniture. Stay away from windows.
  • Secure outdoor objects, if time permits, to prevent them from causing danger due to the tornado's passage.
  • When a tornado is going to hit, it is much better to lie down in any depression or crawl into culverts.
  • When in a vehicle, pull over, leave it, and go outside to the closest ravine, ditch, or depression for cover. (but watch out for flash flooding)
  • Tornadoes are generally short-lived. They come and go quickly. There may not be a time for warning.
  • Be alert for the sudden appearance of violence winds, rain, hail, or funnel-shaped cloud in your locality.
• Drought


  The lack of rainfall for normal needs. It's a cyclical event so it can be predicted. It can be attributed to the El Nino phenomenon and the greenhouse effect of the warming of the earth's surface
• Impacts of drought


  • Agricultural crops will not grow without water
  • Animal will die of thirst
  • Femine or food insecurity
  • The water supply for domestics and industrial use will be reduced
  • There would be less livelihood for people whose jobs are dependent on water supply
  • There would be epidemic and other health problems due to the rise of micro-organism, poor sanitation and hunger
  • High temperature can trigger a wildfire
• Measures to reduce risks due to drought

  • Build structures that can conserve water such as dams, dikes, and irrigation systems.
  • Issue an early warning to prepare the people, communities, and institutions.
  • Conserve water even prior to the occurrence of the drought.
  • Adopt indigenous practices in agriculture which could vary depending on the physical situations and cultures in communities.
  • Preserve and store food.
  • Desalinate water supply.
  • Change lifestyle to adapt to drought.