Initial Attack Operations on a Wildfire

The first control and suppression actions on an wildfire are known as initial attack.  Initial attack crews are able to control 95% or more of all fires by constructing firelines followed by mop up and patrol of hot spots.  Firefighters have the greatest success when fires are attacked early, before the fire reaches flashy fuels or encounters high winds that can produce high spread rates. Early attack also may also preclude the formation of an organized convection column that itself will spur fire growth through the creation of updrafts and downdrafts that can cause the fire to spread quickly. Even so, constant vigilance is required even after a fire is completely encircled with constructed fireline or isolated by natural barriers, to assure that wind gusts do not throw glowing embers across the fireline.

Generally suppression resources will be small in number (as the fire size is relatively small) and may vary from one to several resources such as a tractor plow or several fire engines. The Incident Commander (IC) may request additional support from the dispatcher, such as crews equipped with hand tools, helicopters dropping water from a water bucket, or air tankers with retardant. Usually, the fire will be contained within a single or several work periods (less than 24 hours)--although mop up and patrol may extend over several days or weeks.

Size Up

The size up includes an evaluation by an experienced IC of the fire’s current behavior and projected growth, necessary actions, and required resources to suppress the fire. It takes place iteratively at different stages of a fire’s development--from the initial report, while en-route to the fire, at first sighting of the smoke plume and flames, upon arrival, and throughout the fire control effort. While en-route to the fire, an experienced IC will try to piece together as much information as available regarding the following:

• General location (including proximity to structures) and fuel type in which the fire has been reported;
• History of fire and fire effects in the area, especially if previous fires in similar environments (fuel, weather, topography) have exceeded initial attack capabilities;
• Weather conditions (current and upcoming) for the time of day and year, including recent moisture trends;
• Descriptive statements about the fire’s behavior from observers so far (lookouts, aerial spotters, or general public).

Knowledge of general location could provide additional insights regarding logistics of moving crews, vehicles, and equipment to the fire. The grades and quality of the roads may affect transport speed or possibly preclude or restrict the movement of heavy equipment. Available water sources for refilling fire engine tanks also will vary by location. Time of day, slope, and aspect will provide additional insights regarding likely fire behavior in the hours ahead.

The first sighting of the smoke plume and flames will provide additional information regarding the intensity and likely success of suppression activities. Dark smoke in a billowing convection column can mean a crown fire that will exceed suppression capabilities. If observed en-route to the fire, the IC may decide that attacking the fire’s head may be unsafe and waste valuable time and energy. By contrast, diffuse white smoke will indicate a surface fire burning in moist fuels.

Upon arrival, the IC needs to complete the initial size up, including projections of future fire involvement with fuels, houses, and valued areas--then report back to the dispatcher if the fire can be handled with available resources or if additional forces will be required. The size up should evolve and be re-evaluated throughout the life of the fire, as warranted.