What are wildfires?

wildfire

a large, uncontrolled, destructive fire that burns quickly over woodland or grassland

What are the three types of wildfire?

• ground fires

• surface fires

• crown fires

ground fire

the ground burns (e.g., peat, tree roots) slowly with no flame and little smoke

surface fire

leaf litter and low-lying vegetation burn

crown fire

fire moves rapidly and intensely through the canopy

What conditions are needed for wildfires?

• thick undergrowth

• closely spaced trees

• trees containing lots of oil (e.g., pine, eucalyptus)

• fine, dry material (e.g., twigs)

• flammable plants

• large amounts of fuel

• dry weather/dry seasons/droughts

• high temperatures/heatwaves

• strong winds

• an ignition source

How are wildfires distributed?

• most frequent in hot areas with drought

• on every continent except Antarctica

• mainly rural areas

• now occur within the boundaries of settlements with continued human habitation expansion

• areas most susceptible to wildfires are those with a combination of dry vegetation and lightning strikes

What are some human causes of wildfires?

• sparks from machinery

• cigarettes

• fireworks

• barbecues

• campfires

• arson

• managed fires

What are some natural causes of wildfires?

• lightning 

• volcanic eruptions

What is El Niño?

• a part of the natural climate phenomenon called the El Niño Southern Oscilation (ENSO)

• the ENSO has two opposite states - El Niño and La Niña

• a cyclical climatic condition

• occurs every 6-8 years on average

• involves the warming of the Pacific Ocean off the west coast of South America

• typically declared when sea surface temperatures in the tropical eastern Pacific rise to at least 0.5°C above the long-term average

What does/can El Niño cause?

• significantly affects global patterns of temperature and rainfall

• sends warm surface waters eastwards

• can cause devastating floods in some places and prolonged periods of drought in others

• can create favourable conditions for wildfires

• linked to carbon monoxide pollution plumes

What is the Indian Ocean Dipole (IOD)?

• a cyclical climatic condition/event

• an ocean and atmosphere phenomenon

• affects the climate of countries that surround the Indian Ocean basin

• can be ‘positive’ or ‘negative’

What does a positive Indian Ocean Dipole cause?

• cooler in the tropical eastern Indian Ocean

• warmer in the tropical western Indian Ocean

• decreased rainfall over parts of central and southern Australia

• increased risk of wildfires

What does a negative Indian Ocean Dipole cause?

• warmer in the tropical eastern Indian Ocean

• cooler in the tropical western Indian Ocean