Wildfires Flashcards
What are the conditions which favour intense wildfires?
- Vegatation type
- Fuel characteristics
- Climate and recent weather
- Fire behaviour
How does vegetation type influence wildfires?
- Thick vegetation or closely spaced trees enable fire to travel fast
- Eucalyptus contains lots of oils which burn quickly
- Eucalyptus trees shed trips of bark which also helps fire spread
How do fuel characteristics influence wildfires?
- Fine and dry material catch fire and burn easier
- Large amounts of fuel with large % cover enables fire to burn for longer and spread
How does the climate and recent weather influence wildfires ?
- High rainfall means vegetation growth which increases supply of fuel
- Distinct dry season with low rainfall, warm dry weather causes water in vegetation to dry up meaning plant is more flammable
- High strong winds provide more oxygen to intensify and spread fire
How does fire behaviour influence wildfires?
Creeping vs running fire which is more intense with a rapid spread. FIREBRANDS are burning debris thrown out by a fire helping it to spread
Define wildfire
An uncontrolled fire
What are the 3 types of fire ?
- Ground fire: ground itself burns e.g. peat and tree roots. Slow fire with no flame and little smoke
- Surface fire: Leaf litter and low lying vegetation burn. Can be low or high intensity
- Crown fire: Rapid movement through canopy. Intense and fast moving
LADDER EFFECT - Process of fire moving from forest floor to tree canopy
What are the 3 conditions needed for ignition of a fire ?
- Fuel
- Oxygen
- Heat source
Give 2 natural causes of wildfires
- Lightning if it occurs without much rain present
- Volcanic eruptions produce hot lava, ash or gas which ignites fires
Give 2 human causes of wildfires
- Uncontrolled campfires in vulnerable areas
- Arson
Give a prevention strategy as a long term response to wildfires
- Education on the risks of using campfires in vulnerable areas
Give a preparedness strategy as a long term response to wildfires
Households having an emergency plan with emergency supplies to escape wildfires
Give adaptation strategies as long term responses to wildfires
- Using non flammable building materials
- Creating fire breaks in trees around settlements to control fire spread
- Planting pyrophytic vegetation which is adapted to tolerate fire as high moisture content
What is el nino ?
A cyclic climatic event which occurs every 6-8 years and causes warming of Pacific ocean and affects global patterns of temperature and precipitation
- Clear link between Indonesian fires in 1990s and el nino creating an increased risk for wildfires
What is the Indian ocean dipole ?
An ocean atmospheric phenomenon affecting climates of countries surrounding Indian ocean. Decreases rainfall over Central and Southern Australia, increasing the risk of wildfires
Explain the changing distribution of wildfires
- Every continent has favorable conditions except Antarctica
- Wildfire risk increases proportionally to population increase
- More powerlines and use of machinery
- More vulnerable areas due to climate change
How are wildfires part of a global positive feedback loop?
- Burning increases atmospheric CO2 as stores are released, enhancing the greenhouse effect and creating a positive feedback loop which increases temperatures and increases likelihood of wildfires
