HYDROMETEOROLOGICAL HAZARDS

• Typhoons - originate mainly near the equator due to the presence of warm air and trade winds
• Convective theory - mass of air becomes convectively unstable and moist compared to its surrounding air
• Frontal or Counter-current theory: Many tropical cyclones form along the front between the trade winds and the equatorial air in doldrums
• Four life stages of typhoons:

  • Formative Stage
  • Immature Stage
  • Mature Stage
  • Decaying Stage
• Part of typhoon:

  ★ calm part of the typhoon

  ★ lowest atmospheric pressure

  ★ 10-65 km wide

  ★ clear skies

  Eye
• Part of typhoon:

  ★ strongest winds

  ★ surrounding the eye

  ★ 15 km above sea level

  Eyewall
• Rainbands - spiraling strips of clouds around the eye wall
• Tropical Depression - wind speed up too 61 kph or less
• Tropical Storm - wind speed up ranging from 62 - 88 kph
• Severe Tropical Storm - wind speed up ranging from 89 - 117 kph
• Typhoon - wind speed greater than 118 - 184 kph
• Super Typhoon - wind speed greater than 185 kph
• • is the abnormal rise of water level of a stream that may result in the overflowing by the water
  • comes from heavy rains, overflow of bodies of water, and failure of man-made systems

  Flood
• Flash flood - rapid nature of flowing and covering areas that have little to no absorption capability. rainfall within a period of more than 6 hours
• Storm Surges - overflow of water in coastal areas
• EL NIÑO - weakening of trade winds. brings warm air to the east
• LA NIÑA - strengthening of trade winds. more warm water towards Asia.