Firefighters are implementing an indirect strategy to safely fight the fire while minimizing acres burned. This suppression strategy includes constructing fireline away from the fire’s edge when it is unsafe for firefighters to build a fireline directly adjacent to the fire. This strategy is used when any combination of these factors are present: very active fire behavior with flame lengths longer than four feet; a fast moving fire; heavy amounts of fuel; and/or very steep and cliffy terrain.
Indirect firelines typically use a combination of natural barriers, like ridge tops, combined with dozer or hand built lines. Construction requires an extensive amount of work. Clearing and disposing of the vegetation, often through chipping, removing all vegetation down to mineral soil, and removing ladder fuels adjacent to the line can be very time consuming. Even when using existing roads, thinning and removing ladder fuels are often required immediately adjacent to the road to successfully stop a fire. Fires that move through the tree canopy or in heavy brush can easily move across a road, the goal is to get the fire to drop to the ground and/or reduce its intensity, allowing firefighters a better chance to halt the forward progression of the fire.
Burn outs are often used in conjunction with indirect lines to slow the fire down before it reaches control lines. Burn outs are intentionally set to consume fuels adjacent to the fireline in a controlled manner. “Until we can burn out and have good secure black line, we cannot call a fire contained,” said Lewis. Fires are declared contained when the fireline can reasonably be expected to stop the fire’s spread. To date, many miles of fireline have been constructed, but not yet secured through burn-out.