Suppression of Wildfires

When the decision is made to suppress a fire near a road, an initial attack is made by an engine crew; otherwise, a helitack crew lands as close to the fire as possible. The firefighters take pulaskis and shovels, a chainsaw and fuel, a small portable pump and hose, and their personal line gear. If the fire can’t be suppressed by the initial crew, the Incident Commander orders several squads (groups of 5 firefighters) or crews (20 firefighters) to report to the site by vehicle, helicopter, or on foot. In the case of very large fires, a team involving hundreds of people from all over the country may be called in. Additional equipment and supplies may be staged at a helibase near the fire or longlined into the site on a 100- to 200-foot cable remotely operated by the pilot. Water gel explosives may be used to create fireline with relatively little effort. Another alternative to the laborious digging of fireline is the use of “wetline,” which lessens the effect of fireline on vegetation and erosion. Water sources and dip sites may be located so that portable pumps and hose or bucket drops may be used. Guided by ground personnel via radio, a helicopter pilot may drop retardant and/or water at the edge of the fire to cool it enough for firefighters to remove fuels with hand tools. However, the use of hand crews is not safe or practical when flame lengths exceed 4 feet; engine and heavy equipment use is no longer safe or effective at flame lengths of more than 6 feet; and at flame lengths of 11 feet or more, all suppression techniques become risky and largely ineffective. Timber fuel types found in Yellowstone may generate crown fire flame lengths exceeding 100 feet, with 50 feet being typical. Once the fire is “contained,” the focus shifts to the hard work of mop-up. Each remaining ember is painstakingly sought and put out. The entire fire perimeter, and sometimes the entire fire area, is felt with bare hands to make sure that no heat remains that could allow the fire to revive.