Fire and WildfireGlossary

Firefighting and Wildfire terms and their definitions.

Word	Definition
Air Attack	Using airplanes or helicopters to help control a ground cover fire. Aircraft can also be used logistically to transport crews, supplies, and equipment.
Air Tanker	Any fixed-wing aircraft used to drop retardant or water on a wildland fire.
Anchor Point	A term associated with attack methods. Refers to an advantageous location, usually one with a barrier to fire spread, from which to start constructing a fire line. Used to minimize the chance of being "flanked" by the fire while constructing the fire line. Most anchor points originate at or near the area of origin (rear of fire).
Arson fire	A fire intentionally set by anyone to burn, or spread to, vegetation or property.
Aspect	A topography term for direction towards which a slope faces.
Available Fuels	The portion of the total fuel that actually burns.
Backfire	A fire-suppression technique of creating a firebreak by burning all fuel between the existing fire line and the oncoming fire.When attacking a wildland fire using the indirect attack method, intentionally setting fire to fuels inside the control line to reduce fuel and contain a rapidly spreading fire. Backfiring provides a wide defense perimeter and may be further employed to change the force of the fire's convective column.
Black Line	When putting in control lines, the process of burning out any pockets of unburned fuels.
Blowup	A dangerously rapid increase in fire spread.
Brush	Shrubs and stands of short, scrubby trees that do not reach merchantable size, generally 3' to 20' in height.
Brush Engine	Any light, mobile vehicle having limited pumping and water capacity, designed for initial attack knockdown of a small wildland fire.
Burning Conditions	The environmental factors that affect fire.
Burning Index	A numerical measurement of the difficulty of fire containment. Based on spread component and fire intensity. A number that describes anticipated fire behavior and how difficult it will be to control the fire.
Burning Out	When attack on the wildland fire is direct, or parallel with the control line, intentionally setting fire to unburned islands of fuel inside the control line to strengthen the line.
Camp	A geographic site within the general incident area, equipped and staffed to provide food, water, sleeping, and sanitary services to incident personnel.
Candling	Burning aerial canopy of one single tree from ground up.
Canopy	The leaves and branches making up the "roof " of the forest, and cover the "fuel" on the forest floor.
Cat Line	A fire line constructed by a bulldozer.
Cat Pile	A berm left by a bulldozer that might contain smoldering fuels.
Chain	A unit of measure used in land surveying. One chain equals 66'. This useful measurement determines distance and area. Eighty (80) chains equal 1 mile and 10 square chains equal 1 acre. A fire behavior term used to figure fire perimeter size and rate of spread.
Class A Fire	Fires burning in natural fuels such as wood, paper, or other vegetative fuels.
Class B Fire	Fires burning in hydrocarbon fuels such as gasoline, oil, or diesel.
Clear Text	Use of plain language in radio communication transmissions, non-coded language.
Cold Trailing	To control a partly dead fire's edge by carefully inspecting and feeling with bare hands for any remaining embers or coals.
Combustible material	Any material that can catch on fire and burn.
Combustion	The act of burning.
Command	The act of directing, managing, and/or controlling personnel and resources by virtue of explicit legal, agency, or delegated authority.
Company	Any piece of equipment having a full complement of personnel.
Conduction	The transfer of heat from one place to another without movement of the medium.
Conflagration	A raging, destructive fire. Often used to describe a fire burning under extreme fire weather. The term is also used when a wildland fire burns into a wildland/urban interface, destroying many structures.
Contain Fire	An effort to prevent further spread of the fire. Frefighters or other resources stop the forward progress of a fire but have not put in all control lines.
Control Line	Also often called a "fireline," this includes lines constructed by firefighters as well as natural barriers to fire such as rock outcroppings, roads, and streams or other water bodies. Foresters construct fire lines by using bulldozers, leaf blowers, chainsaws, shovels, pulaskis, and rakes to clear the line of vegetation down to the mineral soil so that the fire will have nothing to burn when it gets to that point. A term used for all constructed or natural fire barriers used to control a fire.
Control of Fire	A fire is considered "controlled" when it is completely surrounded by a "control line," which is expected to keep the fire from spreading further. Firefighters and/or other resources completely surround and leave no open line on the fire perimeter.
Convection	The transfer of heat by physical movement of a heated medium from one place to another. The convective column of a wildland fire can provide the medium.
Cooperative Agreements	Written documents made between unlike governmental bodies (for example state and federal) to provide assistance in terms of emergencies.
Council rake	A long-handled combination rake and cutting tool used in suppressing wildfire and mop-up.
Crawler tractor	A tracked vehicle (often equipped with a front-mounted blade and rear-attached fire plow) used to suppress wildfires.
Crown Fire	Any fire that advances from top to top of trees or brush that is more or less independent of the surface fire.
Defensible space	An area, usually a width of 30 feet or more, between a home or other structure and a potential wildfire where the combustibles have been removed or modified.
Demob	An abbreviation for demobilization. The systematic release of personnel and resources from an incident. Demob should start during the incident's mobilization phase.
Direct Attack	Attacking the fire on its burning edge or close to it. A direct attack is usually made on a wildland fire that is moving slowly and is not too hot for firefighters to operate close to the fire's edge with equipment.
Division	The largest segment of a geographical fire perimeter. A division supervisor is in charge of operational activities with the division. Letters are assigned to describe a division.
Dozer	A heavy piece of equipment used to construct a fire line by clearing vegetation.
Drift Smoke	Smoke that has drifted from its point of origin and lost its original billowing form. Drift smoke can fill in canyons under stable air masses and make it difficult to see spot fires.
Drip torch	A small fuel tank with a handle, nozzle, and igniter used to drip a burning mixture of oil or diesel and gasoline to ignite a prescribed fire or a backfire.
Drop	A term associated with air attack. Refers to dropped cargo, firefighters, or retardant.
Drought Index	A number representing the net effect of evaporation, transpiration, and precipitation in producing cumulative moisture depletion.
Dry Lightning Storm	A lightning storm where little or no rain reaches the ground.
Duff	Matted, partly decomposed leaves, twigs, and bark beneath trees and brush.
Ecotone	The edge between two vegetation types that contain a mixture of both.
Ecosystem	A community where living organisms and non-living components of the environment are acting as a unit.
Engine	A light truck with a water-pump and a limited supply of water used for fire suppression. Any fire vehicle providing specified pump, water, and hose capacities.
Engine Company	Any fire vehicle providing specified pump, water, hose, and a minimum of three firefighters.
Environment	The sum of all external conditions affecting the life, development, and survival of an organism.
Escape route	A route away from dangerous areas or a fire; residents of the wildland urban interface should preplan escape routes to be prepared in the event of a fire.
Engine Company	Any fire vehicle providing specified pump, water, hose, and a minimum of three firefighters.
Extended Attack	Fires that go beyond three burning periods.
Extreme Fire Behavior	When a wildland fire is influenced by adverse winds, fuels, adverse topography, or any combination of the above. High rates of spread, spotting, and thermal outputs are associated with extreme fire behavior.
Fine Fuel Moisture	A term expressing the moisture level (in percentage) found in fine fuels (such as grass).
Finger	Long, narrow extensions from the main body of the fire.
Fire	A
Fire Behavior	The manner in which a wildland fire develops; how fuels ignite, flame development, and fire spread.
Firebrand	Any source of heat, natural or man made, capable of igniting wildland fuels. Flaming or glowing fuel particles that can be carried naturally by wind, convection currents, or by gravity into unburned fuels.
Fire Break	A barrier, man-made or natural, that will stop or slow an oncoming wildland fire.
Fire Danger Rating	The process of evaluating fire danger that integrates the effects of selected factors into one or more qualitative or numerical indices to express current danger or protection needs.
Fire Exclusion	Total or near total elimination of fire from an ecosystem.
Fire Flank	The sides of a wildland fire between the tail and the head. Can be identified with compass directions, left and right, hot or cold.
Fire Flap	A fire tool made of a thick, flat piece of rubber on a long handle used to smother grass fires.
Fire Inclusion	The intentional use of prescribed fire to manipulate an ecosystem.
Fire Intensity	The rate of heat release from an entire fire at a specific point in time.
Fire Line	The part of a control line that is scraped or dug down to mineral soil. See "Control Line."
Fire Perimeter	The entire length of the outer edge of the fire.
Fire Prevention	Activities, including education, enforcement, and administration directed at reducing the number of human-caused wildfires, the cost of suppression, and the cost of related fire damages.
Fire Retardant	Any substance or chemical applied to wildland fuels to slow the rate of combustion or reduce flammability, generally expressed as long-term or short-term. Long-term retardants are generally chemical based, whereas short-term retardants are primarily thickened soapy water.
Fire Season	The period of the year when wildland fires are most likely to occur.
Fire Storm	Violent convective columns caused by large continuous areas of fire, often appearing as tornado-like whirls. Can also occur from uneven terrain as fire spreads through an area. Are associated with extreme fire behavior.
Fire Triangle	A learning tool where the sides of a triangle are used to represent the three factors (oxygen, heat, fuel) needed to catch on fire, burn, and produce fl ame; removing any of the three factors causes the fire to go out.
Firefighter	A person who is trained to suppress structural and/or wildland fire.
Firing Team	Experienced wildland firefighters and firing boss in charge of carrying out backfiring or burn-out function.
Firing Out	Also called firing. The intentional setting on fire of fuels between the control line and the main body of fire in either a backfiring or burning-out operation.
Firewise construction	The use of materials and systems in the design and construction of a building to help keep fire from spreading within a building or to help keep fire from spreading from buildings to the wildland/urban interface area, or vice versa.
Firewise landscaping -	Managing the landscape so that flammable fuels are removed from around a structure to reduce exposure to radiant heat. The flammable fuels may be replaced with: green lawn; gardens; certain individually-spaced green, ornamental shrubs; individually spaced and pruned trees; or, decorative stone or other non-fl ammable or fl ame-resistant materials.
Flanking	Attacking a wildland fire by working the sides of the fire between the head and rear.
Flash Fuels	Fuels like grass, leaves, pine needles, and tree moss that ignite readily and burn rapidly. Also called fine fuels.
Foam	A chemical fire-extinguishing mixture. It attaches to fuels, cooling and moistening them. It also keeps oxygen from the fuel; eliminating one of the items fire needs to burn.
Forest	An ecosystem with dense or not-so-dense tree cover, often containing separate stands of trees, and commonly including meadows and streams.
Forest Technician	An employee of the Virginia Department of Forestry whose duties include fire prevention and wildland firefighting.
Forester	An employee of the Virginia Department of Forestry whose duties include landowner forest management assistance as well as fire suppression.
Fuel	All the dead and living material that will burn. This includes grasses, dead branches and pine needles on the ground, as well as standing live and dead trees. Also included are minerals near the surface, such as coal that will burn during a fire, and human-built structures.
Fuel break	A wide strip, or block of land where the vegetation has been permanently changed or reduced so that fires burning into it can be put out more easily.
Fuel hazard reduction	The treatment and/or removal of living and/or dead forest or wildland vegetation to reduce the threat of wildfire.
Fuel moisture content	The amount of water in a fuel, expressed as a percent of the oven-dried weight of that fuel. The quantity of moisture in fuel given as a percentage of weight when thoroughly dried at 212 degrees Fahrenheit.
Fuel Type	An identifiable association of fuel elements of distinctive species, form, size, arrangement, or other characteristics. General fuel types are grass, brush, timber, and slash.
Gradient Winds	Wind created by differing barometric pressures between high and low air-pressure systems.
Group	Resources assembled at an incident to perform a special function, not necessarily within a single geographic division.
Hand Crew	A group of firefighters organized and trained to clear brush, cut trees, and make fire lines with hand tools.
Head of a Fire	The most active part of a wildland fire. A developing wildland fire can have multiple heads.
Heavy Fuels	Fuels of large diameter such as logs, snags, and large tree limbs. These ignite slowly and burn slow but hot.
Helibase	A location within the general incident area for parking, fueling, maintenance, and loading of helicopters.
Hose Lay	Connecting sections of fire hose together from the fire pump to the fire location with designated sections of line controlled by use of water.
Ignition Component	A rating of the probability that a firebrand will cause a fire requiring suppression action. It is calculated using air temperature, shading, fuel moisture, fuel temperature, wind, slope, and fuel type.
Incendiary Fire	A wildland fire willfully set by anyone to burn wildland or property not owned or leased by this person.
Incident Action Plan (IAP)	The incident action plan contains objectives for the overall incident strategy and specific control actions for the next operational period of an incident.
Incident Commander	The officer in charge of the overall management of the incident. He or she is responsible for building management organization based on a span of control and incident complexity. There is only one incident commander per incident.
Incident Command System (ICS)	A broad term used to describe a management system for all risk incidents. It involves a combination of facilities, equipment, personnel, procedures,and communications operating within a common organizational structure.
Indirect Attack	A method of attack in which the control line is located along a natural barrier, firebreak, creek, river, or paved road. This attack method may be used in conjunction with backfiring.
Initial Attack (IA)	The first-alarm assignment (resources and personnel) dispatched to a wildland incident.
Inversion	A weather term used to describe when, in a given parcel of air, the air temperature increases with altitude.
Ladder Fuels	Fuels (like shrubs and branches) that carry the fire from the ground to the tops of trees, the same way a person would climb a ladder.
Large Fire	A fire of 100 acres or more.
Local Wind	A wind whose velocity and direction is determined by local heating and cooling (diurnal cycle). Local winds are low velocity, averaging less than 10 mph.
Live Fuel Moisture (LFM)	A term describing moisture levels (expressed in percentage) found in brush and trees.
Man Caused Risk	A numerical rating of the potential occurrence of a person-caused fire requiring suppression action per million acres.
Mineral Soil	Soil with little organic matter. Organic soils and organic soil layers can burn. Organic soil layers are often found above mineral soil layers, such as humus layers of decayed leaves in forests ecotypes.
Mop-up	After the fire has been controlled, all actions required to make the fire "safe", prior to being called out. This is the process of making sure all remaining hot spots within the fire's perimeter are completely out, and includes trenching, falling snags, and checking all control lines.
Mutual Aid	An agreement made between like governmental bodies (such as federal and state) to provide assistance to each other in times of emergencies.
Natural Barrier	Any area that does not have flammable material (such as a stream) and can help keep wildfires from spreading.
Nomex	This high temperature resistant, man-made fiber (developed by DUPONT) greatly increases a firefighters protection against injury from burning. The material will not sustain combustion in air and will not melt in the presence of flames. When exposed to intense heat, Nomex carbonizes and becomes thicker to provide a protective barrier between the heat source and the skin. Nomex resists burning at a much higher temp than cotton, any synthetic or other natural fibers. No amount of laundering, or wear or tear can remove the flame resistance from apparel made of Nomex.
Operational Period	The period of time scheduled for execution of a given set of operation objectives as specified in the incident action plan.
Overhead	Personnel who are assigned to supervisory positions. This includes incident commander, command staff, directors, supervisors, and unit leaders.
Overstory	The portion of the trees in a forest that forms the upper or uppermost layer.
Parallel Firing Method	A method where hand-tool crews operate 100 yards parallel to the fire's edge and burn out as they complete the fire line.
Prescribed Burn	A forest management tool where fire is applied in a skillful manner to forest fuels, in a definite place, for a specific purpose, under exacting weather conditions, to achieve manageable objectives, such as to improve forage and habitat for wildlife and livestock, to improve watershed, or to reduce hazardous build up of fire fuels.
Progressive Hose Lay	A hose lay used on a wildland fire, usually on the flanks, to follow up a hand line made by crews or as a means of making a "wet line" along the fire's edge. Major components of this lay include 1 1/2-inch hose as a main feeder line with 1-inch hose branched off it, usually every 100 to 150 feet.
Project Fires	Fires that require a large amount of logistical and service support to suppress. Fires that need a supervisor in each of the five major functions of ICS.
Rate of Spread (ROS)	A fire behavior term used to express relative horizontal growth of a wildland fire. The relative activity of a fire in extending its horizontal dimensions. It can be expressed as a rate of increase for the total perimeter of the fire, as a rate of forward-spread for the fire front, or as a rate of increase in area. It is usually expressed as a rate in chains or acres per hour. Expressed in total perimeter growth in chains per hour.
Rear of Fire	The portion of a fire opposite the head. The slowest burning part of the fire.
Red Flag Warning	A term used by weather forecasters to alert firefighters and citizens to ongoing or approaching fire weather conditions.
Relative Humidity	A weather term, the amount of moisture in the air as a percentage of the maximum the air will hold at a given temperature. The amount of moisture in a given parcel of air expressed as a percentage of the maximum amount that parcel of air could hold at the same air temperature.
Smoke	(1) The visible products of combustion rising above fire. (2) Term used when reporting a fire or probable fire in its initial stages.
Smokey Bear	"Smokey," the fire prevention bear of the U.S. Forest Service, has been our nation's symbol for the prevention of human-caused wildfires since 1944. His message: "Remember . . . only you can prevent wildfires."
Spread Component	A rating of the forward spread of a fire front expressed in feet per minute.
Stewardship	involves integrating the management, protection, and enhancement of the forest's resources, in a manner which meets a landowner's needs and objectives.
Stewardship Forest	A privately owned forest tract that exhibits integrated forest management to protect and enhance wildlife, timber, recreation, natural beauty, and soil and water quality.
Strike Team	Specified combinations of the same kind and type of resources, with common radio communications and leader.
Suppression (of fire)	The act or process of putting a fire out.
Surface Fire	A fire that burns surface litter like dry pine needles and leaves.
Swamper	A term associated with dozer operations. A swamper is the person or relief operator assisting dozer operator(s), often by driving a fuel or service tank.
Task Force	A set of resources with a common leader and communications temporarily assembled for a specific mission. Task forces are generally used for firing operations and structural protection.
Thermal Belts	In mountainous regions, the middle third of the slopes that remain active with fire during evening hours. This is due to down-canyon "falling" winds that pool cooler air in canyon bottoms but leave the middle part of the slope active.
Topography	An accurate and detailed description of a place, including land surface configuration, both man-mad and natural. Topography can be described in terms like "level", "steep", "broken", or "rolling".
Trenching	The action of digging trenches on a side slope to catch any material that might roll across the control lines.
Undercut Line	A control line constructed below a fire on a slope.
Understory	The layer in a forest below the overstory, formed by lower-growing vegetation under the tall trees, like shorter trees or bushes.
Unified Command	A method whereby agencies or individuals who have either geographic or functional jurisdiction at an incident can jointly determine overall objectives, select a strategy and establish common organizational objectives. This may be implemented in a variety of ways and does not compromise the principle of having only one incident commander.
Vegetation	Plant life, or total plant cover of an area.
Virga	A weather term describing moisture falling from clouds but not reaching the earth's surface.
Wet Line	Control line put in by means of a progressive hose lay using 1 1/2-inch feeder line with 1-inch branch lines every 100 to 150 feet.
Wildfire	An unwanted or unplanned fire burning in forests or wildland areas that threatens to destroy life, property, or natural resources.
Wildland	An area in which development is essentially non-existent, except for roads, railroads, power lines, and similar infra-structure improvements.
Wildland/Urban Interface	The line, area, or zone where structures and other human development meet or intermingle with undeveloped wildland or vegetative fuels.
Wildlife	All non-domesticated animal life.
Wind	The horizontal flow of air relative to the earth's topography and surface.
Wye	A hose fitting permitting two or more lines to be taken from a single supply line. Used frequently in progressive hose lays on wildland fires.

Wildland Fire Terminology.

Last modified: Friday, 07-Mar-2008 21:00:05 UTC