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• Hydrometeorological hazards

  Are processes which involve the interaction of the atmosphere, bodies of water and land and which pose threats to lives and human property
• Tropical Cyclone

  Low pressure systems that form over warm tropical waters. They typically form when the sea-surface temperature is above 26.5°C
• Names for tropical cyclones in different regions

  • Hurricanes (North Atlantic, Eastern North Pacific, South Pacific Ocean)
  • Cyclonic (Bay of Bengal, Arabian Sea, Western South Indian Ocean)
  • Willy-willy (Eastern part of the Southern Indian Ocean)
  • Typhoons (Western North Pacific Ocean)
• Tropical Cyclone Structure


  • Average total diameter of 550 km, can be more than 2000 km wide
  • Eye - lowest atmospheric pressure, 20-65 km wide, weak winds, warm temperature, clear sky
  • Eye Wall - region immediately surrounding the center, strongest winds, heavy rains, turbulence
  • Rain Bands - spiraling strips of clouds in the fringes, associated with rainfall
• Effects of Tropical Cyclones


  • Strong Winds
  • Storm Surge
  • Heavy Rains
• Classifications of Tropical Cyclones


  • Tropical Depression (wind speed 61 kph or less)
  • Tropical Storm (wind speed 62-88 kph)
  • Severe Tropical Storm (wind speed 89-117 kph)
  • Typhoon (wind speed 118-184 kph)
  • Super Typhoon (wind speed exceeding 185 kph)
• What to do BEFORE the Tropical Cyclone


  • Store adequate food and water
  • Prepare non-cooked foods
  • Have flashlights, candles, battery-powered radios ready
  • Examine and repair unstable parts of house
  • Stay updated on latest weather reports
  • Harvest crops
  • Secure domesticated animals
  • Place boats in safe area
  • Bring essential items if evacuating
• What to do DURING the Tropical Cyclone

  • Stay inside house
  • Stay updated on latest weather reports
  • Boil water if drinking water not available
  • Keep eye on candles/gas lamps
  • Avoid wading through floodwaters
  • Evacuate calmly if needed
  • Close windows, turn off main power
  • Put important items in high ground
  • Avoid routes near rivers
• What to do AFTER the Tropical Cyclone


  • Check if house is safe to enter
  • Beware of dangerous animals
  • Watch out for live wires/flooded outlets
  • Report damaged cables/posts to authorities
  • Prevent mosquito breeding
• Impending signs of a typhoon

  • Increased ocean swell
  • Changes in clouds
  • Barometric pressure drop
  • Abrupt changes in wind speed
• Storm Surge


  A localized unusual increase of sea water level beyond the predicted astronomical tide level primarily due to intense winds and lowered atmospheric pressure during the passage of an intense tropical cyclone from sea to land
• Buildings, roads, bridges, piers, and other infrastructure may not only submerge, they can also be washed away and destroyed when a storm surge hits an area if they are not strongly rooted on the ground
• Thunderstorm


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


  • Lightning
  • Hail
  • Tornadoes
  • Flash floods
• Flooding


  The abnormal rise of water level in rivers, coastal areas, plains and in highly urbanized centers which may be a result of natural phenomena, human activities or both
• Effects of Flooding

  • Loss of lives and damage to amenities and loss of access to basic necessities
  • Power loss
  • Domestic potable water loss/shortage
  • Risk of acquiring waterborne diseases
  • Economic hardships
• Mitigating Flood Hazard


  • Flood hazard assessment and mapping
  • Flood prediction
  • Flood forecasting and warning
  • Flood-control engineering measures
• What to do BEFORE a flood


  • Tune in to news for updates, flood warnings, evacuation alerts
  • Gather family and inform them
  • Place important/delicate property to higher ground
• What to do DURING a flood


  • Avoid walking/driving through floodwaters
  • Wear boots to avoid electrocution
  • Turn off gas lines/cooking gas tanks
  • Shutdown electricity from control panels
• What to do AFTER a flood


  • Take precautions against risks in compromised/contaminated property
  • Document the damage to your property
• El Niño


  Refers to the large-scale ocean-atmospheric climate interaction linked to a periodic warming in sea surface temperature across the central and east-central Equatorial Pacific
• The presence of El Niño can significantly influence weather patterns, ocean conditions, and marine fisheries across large portions of the globe for an extended period of time
• La Niña


  La Niña is a climate pattern that describes the cooling of surface-ocean water along the tropical west coast of South America
• Tools for Monitoring Hydrometeorological Hazards