Forest Fire Spread Simulator (2D)

Forest

Tree density 72%

Humidity 15%

Wind

Wind speed 50%

Controls

Simulation speed 3.0

Click any tree to ignite it, or drag to clear a firebreak.

Live Readout

Tick

Burning

Trees left

Ash

How it works

Each cell in the grid is a tree, empty ground, or ash. Every tick, a burning cell can ignite each neighboring tree with a probability set by the spread chance, reduced by humidity (damp fuel resists ignition) and boosted downwind (embers and radiant heat travel with the wind). This is the Drossel–Schwabl forest-fire cellular automaton (1992) — the same mathematics also models epidemics, pest outbreaks and rumor spread through a network of neighbors.

Wind does not just speed up the fire, it gives it a direction: cells downwind of a burning tree catch far more easily than cells upwind, so the fire front stretches into a long tongue rather than expanding as a neat circle. Raise humidity and the same fire can stall out and self-extinguish before reaching the edge of the forest.

Drag on the grid to clear a firebreak and see whether it stops the front.
Click a live tree to ignite it directly.

Tree Burning Ash / cleared