Which firefighting technique is used to create a barrier to stop the spread of fire?

Backburning is a firefighting technique that involves intentionally igniting a controlled fire along the inner edge of a fire line to consume the fuel in the path of a wildfire. This technique creates a barrier, effectively stopping the spread of the primary fire. By reducing the available fuel, the backburn diminishes the intensity of the main fire and helps to protect areas that are not yet affected.

This method is particularly useful in managing large wildfires, as it creates a controlled zone where firefighters can operate safely while also allowing them to direct the fire's behavior to their advantage. The successful execution of backburning requires careful planning and precise conditions to ensure that the controlled fire does not escape and create additional hazards.

In contrast, options like overhaul and knocking down refer to processes that occur after a fire is controlled or extinguished, focusing on ensuring that the fire is fully out and that no hotspots remain. The flanking attack involves approaching the fire from the sides to minimize its spread but does not create a barrier in the same way backburning does. Therefore, backburning is the technique specifically designed to establish a defensive line against the advancing fire.