Glossary of Wildfire Terms

Fire behavior: The manner in which a fire reacts to the influences of fuel, weather, and topography.
Fire camp: Temporary camp established at large fires to provide food, rest, and other necessities to fire crews.
Fire cycle
Fire danger
Fire ecology
Fire edge: The boundary of a fire at a given moment.
Fire fighting foam: The aerated solution created by forcing air into, or entraining air in water containing a foam concentrate by means of suitably designed equipment or by cascading it through the air at a high velocity. Foam reduces combustion by cooling, moistening and excluding oxygen.
Fire lookout tower: A structure located at a high vantage point to house and protect the person performing the duties of a Fire Lookout.
Fire Lookout: A person that keeps an eye for possible fire starts and conditions. They can work in a Fire Lookout Tower or perform the duty as a role for a fire crew on the fireline.
Fire rake: A rake with sharpened teeth instead of blades, for raking fire breaks.
Fire retardant: Any substance (except plain water) that by chemical or physical actions reduces flammability of fuels or slows their rate of combustion. See retardant slurry, AFFF, and Foam as examples.
Fire risk
Fire shelter: An aluminized tent offering protection by means of reflecting radiant heat and providing a volume of breathable air in a fire entrapment situation. Carried as a safety tool, fire shelters should only be used in life-threatening situations, as a last resort, as severe burns or asphyxiation often result.
Fire shirt: Distinctive yellow shirts made of Nomex or other lightweight materials of low combustibility, used as uniform PPE of wildland firefighters, and more recently available in other colors (red, khaki, blue, etc.).
Fire trail: Australian term for fireroad, road built specifically for access for "fire management purposes".
Fire weather: weather conditions that affect fire vulnerability, fire behavior and suppression.
Fire whirl: a tornado-like vortex that forms from the stretching of vorticity due to the interaction of air flowing towards and upwards in a fire.
Fire-Return Interval
Fireline handbook: A small red booklet carried by U.S. firefighters on the firelines, as a quick reference on various firefighting topics.
Fireline: The part of a control line that is scraped or dug to mineral soil. Also called fire trail. More generally, working a fire is called being "on the fireline." May also refer to a "wet line" where water has been used to create a burn boundary in light fuels such as grass.
Firestorm: Extreme fire behavior indicated by widespread in-drafts and a tall column of smoke and flame, where added air increases fire intensity, creating runaway fire growth.
Firebreak: A natural or constructed barrier used to stop or check fires that may occur, or to provide a control line from which to work.
Flanks of a fire: The parts of a fire’s spread perimeter that grow to the sides then run roughly parallel to the main direction of spread. Separated flank heads are extremely dangerous in steep terrain.
Flare-up: Any sudden acceleration in rate of spread or intensification of the fire. Unlike blowup, a flare-up is of relatively short duration and does not radically change existing control plans.
Flash fuels: Fuels such as grass, leaves, draped pine needles, fern, tree moss and some kinds of slash, which ignite readily and are consumed rapidly when dry.
Fuel load: the mass of combustible materials available for a fire usually expressed as weight of fuel per unit area (e.g., 20 tons per acre).
Fuel moisture: Percent water content of vegetation, an important factor in rate of spread, ranging from dead-fuel and fine-fuel moisture (FFM), of 10 percent or less, to live-fuel moisture (LFM), of 60 percent or more. FFM can be estimated by weighing calibrated wood sticks.
Fuel type: An identifiable association of fuel elements of distinctive species, form, size, arrangement, or other characteristics that will cause a predictable rate of spread or resistance to control under specified weather conditions.
Fuelbreak: A natural or manmade change in fuel characteristics which affects fire behavior so that fires burning into them can be more readily controlled.