Hazards 6 Wildfires

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Causes of Wildfires:

  • Can be ignited by a human or natural cause
  • Quasi-natural: when a normally benign natural condition or natural process is made more disastrous by human activity
  • In the US it is estimated that 90% of wildfires have a human cause
  • Controlled fires can be used to clear land e.g. slash and burn
  • ignition:
    • Lightning (the climate can affect the frequency of electrical storms)
    • Human intervention (falling power lines, discarded cigarettes, campfires, etc.)
    • Arson
  • fuel: 
    • Enough to burn
    • Dry 
    • Climate affects this, as drought causes the area to dry out
    • Vegetation type e.g. eucalyptus
  • Dry winds e.g. the Santa Ana wind in California descends from the local mountains spreads the fires and makes them difficult to control

Nature of Wildfires:

  • Travel faster on sloped ground
  • Convection currents and strong winds can ignite isolated spot fires
  • Burning fragments of vegetation (firebrands) can roll downhill due to gravity and start other fires

Distribution:

  • Rural hazard
  • Occur on the boundary of substantial settlements
  • Areas with dry seasons
  • Parts of Australia, USA, Canada, Southern Europe

The Need for Wildfires:

  • Fire can clear

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