Wildfire Spread: Percolation, Wind, Slope and Firebreaks - Rothermel-style spread on a lattice

Use the Firebreak tool (bottom bar) and drag on the ground to clear a strip, or draw one automatically across the downwind side.

Show the theoretical fire ellipse from the first ignition point

A. Tree-density sweep. Lights the whole left edge of a random forest of density p and counts how often the fire reaches the right edge, for lattices of 32, 64 and 128 cells, with the neighbourhood chosen above. The 50 % crossing is the percolation threshold p_c (exact 0.5927 for 4 neighbours, 0.4073 for 8).

B. Fire ellipse check. Point ignition on flat ground for several wind speeds and two wind directions; measures head rate and width against the Rothermel + Anderson prediction.

C. Firebreak width. A line fire meets a break of width 0...6 cells with ember spotting; how often does the fire jump it?