storm hazards

• Tropical storm


  Low pressure, spinning storm with high winds and torrential rain
• Conditions for a tropical storm to form and develop


  1. Temperature: Ocean temperatures must be around 26 - 27°C and at least 50 metres deep

  2. Air pressure: Must be in areas of unstable air pressure - usually where areas of high pressure and low pressure meet (convergence)

  3. Wind shear: Winds must be present for the swirling motion to form, but not too strong

  4. Rotation: Tropical storms only form around the equator, but no less than 5° on either side

  5. Trigger: a pre-existing thunderstorm, a spot of very high sea surface temperature, an area of low pressure and many other factors
• Formation of a tropical storm

  1. Warm, moist air rises, leaving an area of low pressure below

  2. Warm air from surrounding areas of higher pressure moves into this low pressure area and rises too

  3. Warm air cools, condensing into thunderstorm clouds

  4. The whole system is spinning due to the Coriolis effect

  5. Constant additions of energy from the warm air causes the storm to spin faster and generate higher wind speeds

  6. Eye of the storm is an area of extremely low pressure with cool, dry air descending

  7. Surrounding the eye is the eyewall, the most intense and powerful area of the storm

  8. When the tropical storm reaches a coast, the low pressure and high winds will cause a storm surge

  9. When the storm reaches land, the eye eventually collapses and heavy rain can persist for days
• Saffir-Simpson Scale


  A scale of 1-5 to measure the magnitude of a tropical storm based on wind speed and power
• Tropical storms form in the Northern Hemisphere from June-November, and the Southern Hemisphere from November-April
• The majority of tropical storms do not develop into strong storms and do not reach land
• Tropical storms that are higher magnitude and reaching land are thought to be increasing in frequency
• Regularity of tropical storms


  Irregular because their path does not follow a set route - the route taken is dependent on the storm and the climatic conditions
• Predictability of tropical storms

  • Satellite tracking of cloud formations and movement can be tracked and the general route can be predicted, especially as the storm gets closer to land
  • Storm surges can also be predicted based on the pressure and intensity of the storm
  • Scientists have predicted how many years it will take for a tropical storm to hit certain areas
• Hazards caused by tropical storms

  • High winds
  • Flooding - coastal/river flooding from storm surges and heavy rain
  • Landslides - due to soil becoming heavy when wet with high levels of rain
  • Storm surges - Large rise in sea levels caused by low pressure and high winds, pushing water towards the coast
• Primary effects of tropical storms


  • Beaches eroded
  • Sand displaced
  • Coastal habitats such as coral reefs are destroyed
  • Businesses destroyed
  • Agricultural land damaged
  • Drowning
  • Debris carried by high winds can injure or kill
  • Buildings destroyed
• Secondary effects of tropical storms

  • River flooding/ salt water contamination
  • Animals displaced from flooding e.g. alligators
  • Water sources changing course from blockages
  • Rebuilding and insurance payout
  • Sources of income lost
  • Economic decline from sources of income destroyed
  • Homelessness
  • Polluted water supplies spread disease
  • Food shortages from damaged land
  • Issues paying back international aid
  • Pressure for government to do more about global warming
• prevention

  • in current climates and weather conditions, tropical storms cannot be avoided.
  • strategies to mitigate climate change could prevent higher category storms
• preparedness

  • awareness through education of what to do during a tropical storm
  • evacuation plans and training
  • satellite image tracking to manage the areas that are at risk
  • storm warning systems and television broadcasts tracking the storm
• mitigation

  • search and rescue, immediate emergency aid, evacuation (short term)
  • strengthening the home through door barricades , roof strengthening etc.
  • clearing loose debris before storms
• adaptation

  • move away from area at risk
  • design buildings to withstand high winds and flood damage
  • flood defenses such as houses on stilts , coastal walls, river levees etc.