Ground Control on Wildfires

Fireline building techniques

Techniques for building a fireline depend on the type of crew and tools available for clearing or removing unburned fuel from the oncoming fire.  Common line building techniques are the hand-over-hand method, the progressive method, and the one-lick method.

• In the hand-over-hand method, each worker is assigned a particular task, such as cutting shrubs or scraping litter and duff. Upon completion of the assigned task, the worker walks to the head of the fireline, passing other crew members along the way (yelling “Coming through!” as needed), then is assigned a new section of line by the crew leader.
• A hand crew with a full complement of cutting and scraping tools may use the progressive method, where each crew member keeps an assigned place in line, working an assigned task until encountering the section being worked on by the firefighter ahead. At that point the crew member will shout “Bump up!” and all workers ahead will advance to the next section of uncleared line and resume work.
• With the one-lick method, each crew member quickly swipes away the fuel in one spot and steps incrementally along the fireline while maintaining safe spacing between adjacent workers. The one-lick method is best suited to cover types requiring a variety of tools, with skilled leadership and a dedicated crew, where each person is willing to do an equal share of work (Chandler and others 1983).

Other line building activities in direct attack include hot-spotting, cold trailing, and burning out.

• Hot-spotting involves cool down or removal of heat concentrations in the fastest advancing fire fronts—essentially a delaying tactic to allow people on the ground to complete the job of building a continuous fireline. On the ground, hot-spotting might involve a fire engine using water, or hand crews throwing shovels of dirt at the base of flaming zones. On large fires, airtankers may drop retardant on hot spots.
• Cold trailing is a tactic that involves the construction of a minimal fireline along a relatively cool portion of a fire to assure that the fire does not spread. A fire may cease to burn actively for two basic reasons: insufficient fuel to support active combustion or change in weather, such as an increase in humidity. Firefighters working the edge of a fire that appears to be out or smoldering with occasional flare-ups are sometimes instructed to cold trail while “keeping one foot in the black.” This admonition recognizes that the burned side of the fireline is cool enough to work safely at the edge. At the same time, should flare-ups occur and threaten fire crews, the black area can provide a possible safety zone. Unfortunately, 11 firefighters who were cold-trailing in chaparral perished in the 1966 Loop fire because they were unaware of a blowup that occurred downslope and quickly pushed the fire uphill. This example illustrates that even a seemingly innocent fire that is nearly out may become a dangerous threat.  
• Burning out is a practice used to secure a constructed fireline. Fire is used to clean up unburned fuel between the constructed line and the edge of the burned area. Unburned fuel pockets resulting from irregular burning are common even in the most severe wildfire. If let unattended, these fuel patches can become future problems areas; if for example, the winds shift and the area re-burns. The practice of burning out is distinguished from a backfire, which is set to remove fuel from an oncoming wildfire. Burning out is essentially a defensive tactic to secure constructed fireline, while backfiring always creates more fire that itself could add to the problems of controlling a major fire advance.