Differentiate between a backing fire and a heading fire.

Differentiate between a backing fire and a heading fire.

• A. A backing fire moves with the wind and spreads rapidly; a heading fire moves against the wind and spreads slowly
• B. A backing fire moves against the wind and spreads slowly; a heading fire moves with the wind and spreads rapidly
• C. Both types move with the wind but differ in flame color
• D. A backing fire is always hotter than a heading fire

Answer: (B)

The key idea here is how wind direction changes how fast a fire spreads. A backing fire moves against the wind, and the wind tends to push heat back into the burned area, making it harder for new fuel to reach ignition and slowing the front’s progress. In contrast, a heading fire travels with the wind; the flames tilt toward unburned fuel ahead, preheating and drying it and delivering more oxygen, so the front advances quickly. So the description that a backing fire moves against the wind and spreads slowly, while a heading fire moves with the wind and spreads rapidly, captures the real behavior of these two fire fronts.