Causes of wildfires - california (case study)

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  • Created by: roseb00d
  • Created on: 27-04-23 20:25
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  • causes of wildfires - California (case study)
    • Topography
      • The two Mountain Ranges
        • southern coast range
          • mountain range by the coast forces the prevailing wind hitting the coast up the mountain
            • this causes adiabatic cooling, this leading to condensation at the top of the mountains
              • Adiabatic cooling is the process of reducing heat through a change in air pressure caused by volume expansion
          • there is a greater amount of rainfall here due to relief rainfall
        • sierra navada
          • the mountain range further inland
            • processes happen here as they do at the southern coast range hut with drier air
              • this leading to extremely dry air on the other side
                • there is a desert on the other side mojave desert also called death valley
      • San Joaquin Valley
        • as the air travels down from the south coast ranges it heats up again (adiabatic heating)
          • this causes a dry wind to fall onto san joaquin valley
        • san joaquin valley is the valley in between the two mountain ranges
          • there is a rainshadow effect due to this causing the area to be drier
      • Relief
        • the steep edges of the mountain provide perfect conditions for a wildfire to spread
          • if the wildfire starts at the bottom of the hill it will catch onto the trees above it extremely easily
            • this is most prevelent in the valley due to the rainshadow effect leading to drier trees/ overall conditions
              • there is a rainshadow effect due to this causing the area to be drier
    • Climate
      • Seasonal wind (santa ana)
        • strong dry winds in the autumn and winter
          • the provides oxygen - fuel- to any potential fire
          • it also pushes the flame front forwards
      • low relative humidity
      • other winds
        • Diablo winds, a dry current that flows from the east or northeast and down into the San Francisco Bay area, is often linked as a contributing factor that helps prolong the fire season.
          • these winds blow from the desert regions of Nevada down to sea level,
            • they warm the area by around 20C
              • compressional heating and lose much of its humidity, triggering and spreading wildfires.
    • vegitation
    • humans
      • 85-90% of wildfires are caused by human activities and negligence, providing the heat source it needed to ignite
        • the El Dorado Fire in 2020, a forest fire that eventually burned down 13,715 acres  due to a malfunctioning smoke-generating pyrotechnical device at a gender reveal party.
    • Wild Fires 2020
      • California experienced its worst wildfire season on record, in which the Bay Area fire became one of the largest wildfires in American history
      • the El Dorado Fire in 2020, a forest fire that eventually burned down 13,715 acres  due to a malfunctioning smoke-generating pyrotechnical device at a gender reveal party.
      • the state recorded up to nearly 10,000 blazes
        • that burned down over 4 million acres of land,
          • accounting for more than 4% of the state’s total land area
    • solutions
      • California Wildfire and Forest Management Task Force was created
        • efforts to reduce wildfire risk for vulnerable communities, improve the health of forests and wildlands, and combat climate change
      • the national conservancy
        • Promote Ecological Forest Restoration and fuels reduction
        • Invest in policies and programs that promote fire resilient communities by directing growth away from high fire risk zones and creating options for communities already in harm’s way.

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