Wildfire Spread & Mitigation Lab
A wildfire spreads cell by cell across vegetation, driven by wind, dryness, fuel, and the slope of the land. Ignite a fire on the left edge, set the conditions, and add a firebreak in front of the town. Run the simulation to watch the fire front move and find out whether the town is contained, saved by a firebreak, or lost.
Guided Experiment: How wide a firebreak is needed to stop a wind driven fire?
Set up a dry, windy fire pushing toward the town, then add a firebreak and widen it step by step. Predict the firebreak width at which the fire can no longer reach the town.
Write your hypothesis in the Lab Report panel, then click Next.
Fire Spread Map
Controls
Dry air, strong downwind, dense fuel, and steep upslope terrain all speed the fire. A wide cleared firebreak between the ignition and the town removes the fuel and can stop the head fire.
Current Readings
Firebreaks, humidity, and wind are the levers. A cleared strip removes fuel, high humidity dampens ignition, and strong downwind speeds the spread toward the town.
Data Table
(0 rows)| # | Wind(0-100) | Direction | Humidity(%) | Slope(°) | Fuel density | Firebreak(cells) | Burned(%) | Town | Outcome |
|---|
Reference Guide
The Fire Triangle and Spread Drivers
A fire needs three things at once, fuel to burn, heat to ignite it, and oxygen to sustain it. Take away any side of this fire triangle and the flame goes out. Wildfire behavior is the story of how those three sides combine across a landscape.
The main drivers of spread are wind, fuel moisture, fuel load, and slope. Wind tilts the flames forward and carries embers downwind. Dry air pulls moisture out of the vegetation so it lights more easily. Dense, continuous fuel lets the fire carry from plant to plant. Steep slopes preheat the fuel above the flames so fire runs uphill fast.
The Cellular Automaton Model
This lab divides the landscape into a grid of cells. Each cell is bare ground, unburned vegetation, actively burning, or burned out. At every time step, a burning cell rolls the dice against each neighboring vegetation cell to decide whether the fire jumps across.
The chance of a jump rises with downwind direction, lower humidity, and uphill slope, and falls upwind and downhill. A burning cell stays alight for a couple of steps and then turns to ash. The same conditions and starting layout always produce the same fire, so you can change one lever at a time and compare.
Firebreaks and Defensible Space
The clearest way to stop a fire is to remove its fuel along a line. A firebreak is a strip cleared of vegetation, by hand, by machine, or as a road or river, that the flames cannot cross because there is nothing to burn.
Around homes, the same idea is called defensible space. Clearing brush and thinning trees near a structure removes the fuel that would carry a fire to the walls and gives crews room to defend it. A wide enough cleared strip can stop even a wind driven head fire, as you can test in this lab.
Real Wildfire Behavior
Forecasters issue a red flag warning when low humidity, dry fuel, and strong wind line up, the same conditions that produce the most dangerous fires in this model. Those are the days when a small spark can become a fast moving wildfire.
Land managers reduce that danger ahead of time with fuel breaks, prescribed burns that thin out built up vegetation, and rules for defensible space around buildings. The goal is to break the fuel up so that when a fire does start, it has fewer ways to grow and more places to stop.
