Fire is not always a disaster. Many forests and grasslands are built to burn, and some seeds will not open without heat. A wildfire becomes a catastrophe when the wrong fire meets the wrong place at the wrong time — when fuels have built up for decades, when the wind will not stop, and when people live where the vegetation is ready to burn.
Play the Wildfires quiz~4 M km²
Burn each year worldwide
90%
Started by people
~50%
Of Australia is fire-prone
3
Things fire needs: heat, fuel, oxygen
How a fire behaves
Weather, fuel and terrain decide almost everything.
The fire triangle
Heat, fuel and oxygen. Remove any one and the fire stops — which is why retardant, clearing and backburning work at all.
Fuel load and ladder fuels
Decades of unburnt leaf litter, bark and dense understorey let a ground fire climb into the canopy, where wind drives it far faster than anyone can walk.
Weather is the multiplier
Low humidity, high temperature and strong, shifting wind decide whether a fire is a manageable line or an unstoppable front. Wind-driven embers start spot fires kilometres ahead.
Terrain funnels it
Fire runs uphill faster than downhill because the flames preheat the slope ahead — the reason ridge lines and gullies are the most dangerous ground.
Three kinds of fire
Ground fires smoulder in peat and roots, surface fires burn litter and grass, and crown fires tear through treetops. Crown fires are the ones that kill.
Fire as ecology
Some landscapes are only healthy when they burn.
Fire-adapted plants
Banksias and some pines need heat to release seed, eucalypts resprout from protected buds, and lodgepole pines drop seed onto bare, ash-enriched soil.
Cultural burning
Aboriginal Australians and many North American nations burned small, cool fires for tens of thousands of years, keeping fuels low and country open.
The suppression paradox
A century of putting every fire out lets fuel accumulate, so the fire that finally escapes burns hotter and larger than the frequent small ones it replaced.
What returns after
Ash returns nutrients in a flush, and the first season after a fire is often the most fertile — which is also when rain on bare slopes causes the erosion and debris flows.
The great fires
Big fires are measured in area, not in headlines.
Black Summer, Australia
About 18.6 million hectares burned, over 3,000 homes were lost and an estimated three billion animals were killed or displaced.
2019–20
Peshtigo, Wisconsin
A firestorm killed between 1,200 and 2,500 people in one night — the deadliest wildfire in recorded history.
1871
Indonesia peat fires
Smouldering peat across Kalimantan and Sumatra produced a haze that covered Southeast Asia and is linked to tens of thousands of premature deaths.
1997
Canada
Roughly 18.5 million hectares burned, and smoke crossed the Atlantic to reach Europe — a signal that fire seasons are now continental in scale.
2023
Greece and the Mediterranean
Heat-driven fires forced the largest evacuation in Greek history, from Rhodes alone.
2023
Black Saturday, Victoria
173 people died in a single day as fires ran under extreme heat and wind — Australia's worst fire disaster.
2009
Living with fire
The house usually survives the front and loses to the embers.
Embers are the killer
Most homes lost in a wildfire are ignited by wind-blown embers landing in gutters, vents and decks long before the flame front arrives.
Defend the last 50 metres
Clearing fuel, removing bark mulch and enclosing subfloor gaps does more than any distant firebreak. Fireproof cladding helps only if the fuel next to it is gone.
Leave early, not late
Late evacuation on a smoke-darkened road is the single biggest cause of death. The safe decision is made hours before the fire is visible.
Prescribed burning and thinning
Planned low-intensity burns and mechanical thinning lower fuel loads, but they need windows of safe weather — those windows are shrinking as the climate warms.
A longer, overlapping season
Fire seasons that once barely met are now overlapping across hemispheres, so crews and aircraft cannot be shared as they once were.
Did you know?
- Some wildfire smoke travels thousands of kilometres — Canada's 2023 fires dimmed skies over New York and reached Europe.
- A single large fire can generate its own weather, including pyrocumulonimbus clouds, lightning and fire tornadoes.
- Grass fires move faster than forest fires because the fuel is fine and continuous; they can outrun a car on a rough track.
- Peat fires are the hardest of all to extinguish — they smoulder underground for weeks or months and can reignite after rain.
- Roughly nine in ten wildfires are started by people — cigarettes, machinery, powerlines, escaped campfires and deliberate lighting.