Current wildfire behavior models treat fire lines as local phenomena. The fire burns, consumes fuel, produces heat, and moves forward. The environment — wind, humidity, terrain — is treated as input to the fire, not output from it.
Linn and colleagues identify the missing mechanism: wildland fire entrainment. A fire doesn't just respond to wind. It creates wind. The buoyant updraft above a fire creates pressure gradients that pull surrounding air toward the combustion zone. This entrained air carries oxygen (feeding the fire), moisture (affecting combustion chemistry), and momentum (altering the fire's own spread direction).
The entrainment length scale — the distance over which a fire influences its surrounding atmosphere — varies with intensity, ambient wind, and terrain. A high-intensity crown fire entrains air from hundreds of meters away. This means fires are nonlocal: the behavior at one point depends on conditions far beyond the combustion zone, mediated by the fire's own atmospheric modification.
This explains several persistent failures in fire management. Counterfire operations — deliberately setting fire ahead of a wildfire to remove fuel — sometimes fail because the main fire's entrainment pulls the counterfire backward, toward the firefighters. Prescribed burns behave differently from predictions because the models don't account for the burn's own wind field, which scales with size (the larger the burn grows, the stronger its entrainment, creating a feedback that accelerates growth).
The through-claim: when a system modifies the conditions it depends on, treating those conditions as external inputs is not a simplification. It's a category error. The fire is not in the wind. The fire is making the wind. And the models that treat environment as background instead of feedback will be wrong in proportion to the system's power to reshape its own context.