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PMS 205

NWCG Glossary of Wildland Fire

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NWCG Glossary of Wildland Fire, PMS 205

Overview

The NWCG Glossary of Wildland Fire provides an extensive listing of approved terms and definitions used by the NWCG community. It contains terms commonly used by NWCG in the areas of wildland fire and incident management and is not intended to list all terms used by NWCG groups and member agencies. The NWCG has directed that all committee and subgroup product glossaries be contained within the NWCG Glossary of Wildland Fire to maintain definition consistency and clarity among documents.

Comments, questions, and recommendations shall be submitted to the appropriate agency program manager assigned to the Data Standards and Terminology Board (DSTB). 

NWCG Glossary of Wildland Fire, PMS 205  (Quick View)

EDG Explorer is a database platform used for managing NWCG Glossary terms.  The following table is a quick view of the terms found in EDG. More detailed information such as rules, documentation, and term relationships may be viewed in EDG Explorer.  

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Term Steward Status Definition
all-lead projectile CEPC Communication, Education, and Prevention Committee In Development
alligatoring CEPC Communication, Education, and Prevention Committee Approved Char patterns formed on paint or burned wood remains, usually in the shape of blisters.
allocated resources IBC Incident Business Committee Archived Resources dispatched to an incident, that have not yet checked in.
allowable payload NIAC National Interagency Aviation Committee Approved The amount of weight that is available for passengers and/or cargo. On the load calculation form it is the operating weight subtracted from the selected weight.
altimeter setting NIAC National Interagency Aviation Committee Approved The barometric pressure reading used to adjust a pressure altimeter for variations in existing atmospheric pressure or to the standard altimeter setting (29.92) inches.
ambient air FWS Fire Weather Subcommittee Approved According to the American Meteorological Society, background, environmental, or surrounding air.
ambulance RMC Risk Management Committee Approved A ground transport vehicle configured, equipped and staffed to respond, care for and transport a patient(s) and approved by a state to do.
ambulate EMC Emergency Medical Committee Approved To move from place to place, walk.
anaphylaxis EMC Emergency Medical Committee Approved Hypersensitivity (as to foreign proteins or drugs) resulting from sensitization following prior contact with the causative agent.
anchor point IOSC Incident Operations Subcommittee Approved An advantageous location, usually a barrier to fire spread, from which to start constructing a fireline. The anchor point is used to minimize the chance of being flanked by the fire while the line is being constructed.
anemometer FWS Fire Weather Subcommittee Approved According to the American Meteorological Society, the general name for instruments designed to measure total wind speed.
angle GSC Geospatial Subcommittee Approved Angle of point symbol displayed in mapping application
animal contact CEPC Communication, Education, and Prevention Committee In Development Power: Simultaneous contact, or arching, between an animal and electrical equipment, either phase-to-phase or phase-to-ground, resulting in electrocution and short circuits. Other: An ignition that occurs when a wild or domestic animal makes contact with electrical equipment such as a power line or electric fence.
annual certification IPSC Incident and Position Standards Committee Approved Annual review by an employing agency of an individual's position qualifications and documentation certifying that the individual is fully qualified to perform duties and responsibilities for a specified position. Annual certification is based on established performance standards and agency specific requirements. 
Annual Operating Plan (AOP) [fire weather] FWS Fire Weather Subcommittee Approved A procedural guide which describes fire meteorological services provided within the Geographic Area of responsibility, including the National Interagency Fire Center. The guide is based on the National Interagency Agreement and applicable Geographic Area Memorandum of Agreement. 
annual plant FDSC Fire Danger Subcommittee Approved A plant that lives for one growing season, starting from a seed each year.
anticyclone FWS Fire Weather Subcommittee Approved According to the American Meteorological Society, an atmospheric anticyclonic circulation, a closed circulation. The wind in an anticyclone is in the clockwise direction in the Northern Hemisphere.
antiemetic EMC Emergency Medical Committee Approved An agent that reduces or prevents vomiting.
apparatus ETC Equipment Technology Committee Approved A motor-driven vehicle, or group of vehicles, designed and constructed for the purpose of fighting fires. May be of different types such as engines, water tenders, ladder trucks, etc.
apparatus identifier ETC Equipment Technology Committee Approved The alphanumeric characters assigned to an apparatus.
apparatus number NCSC National Coordination System Committee Archived The external alphanumeric value painted on the side of the equipment.
approved IOSC Incident Operations Subcommittee Archived In fire service terminology, that which is inspected and listed by recognized fire-testing agencies. The term as used in National Fire Protection Association standards means approval by the authority having jurisdiction, such as the fire chief, insurance inspection department, or other agency that enforces standards or regulations. 
Aramid RMC Risk Management Committee Approved The generic name for a high-strength, flame-resistant, synthetic fabric used in the shirts and jeans of firefighters. Nomex ® , a brand name for aramid fabric, is the term commonly used by firefighters.
arcing/clashing CEPC Communication, Education, and Prevention Committee In Development Electric arc: continuous, high-density electric current between two searated conductors in a gas or vapour with a relatively low potential difference, or voltage, across the conductors. Conductor clashing occurs when energized wires accidentally come into contact with each other.
arduous duty level RMC Risk Management Committee Archived Arduous duty field work requires above-average endurance and superior conditioning.  Duties may include an occasional demand for extraordinarily strenuous activity in emergency situations under adverse environmental conditions over extended periods. The pace of work typically is set by the emergency condition.  Essential functions include, but are not limited to: running, walking or hiking, climbing, jumping, twisting, bending, lifting more than 50 pounds, and carrying 45 pounds or more for extended periods over difficult terrain. 
area command NIMSIC National Incident Management System Integration Committee Approved An organization that oversees the management of multiple incidents or oversees the management of a very large or evolving situation with multiple ICS organizations.
area coordination center IBC Incident Business Committee, NCSC National Coordination System Committee Approved A facility which serves as a central point for one or more agencies to use in processing information and resource requests. It may also serve as a dispatch center for one of the agencies.
area ignition FUSC Fire Use Subcommittee Approved Ignition of several individual fires throughout an area, either simultaneously or in rapid succession, and so spaced that they add to and influence the main body of the fire to produce a hot, fast-spreading fire condition.
area of influence IOSC Incident Operations Subcommittee Approved Delineated area surrounding a base which can be reached first by the ground or air attack units assigned to the base.
area source FUSC Fire Use Subcommittee Approved A source category of air pollution that generally extends over a large area. Prescribed burning, field burning, home heating, and open burning are examples of area sources.
armed IAB Interagency Airtanker Board, SEATB Single Engine Airtanker Board Approved A term used to indicate that the airtanker dropping mechanism is set to allow a programmed release of part or all of the load of fire retardant.
arrest WFISC Wildland Fire Investigation Subcommittee Approved The taking or keeping of a person in custody by legal authority, especially in response to a criminal charge.
arson CEPC Communication, Education, and Prevention Committee In Development At common law, the malicious and willful burning of another's dwelling, outhouse, or parcel; by most modern statutes, the intentional or wrongful burin gof someone else's, orone's own property. Frequently requires proof of malicious or wrongful intent.
arson WFISC Wildland Fire Investigation Subcommittee Approved At common law, the malicious and willful burning of another's dwelling, outhouse or parcel; by most modern statutes, the intentional and wrongful burning of someone else's, or one's own, property. Frequently requires proof of malicious or wrongful intent.
arson fire WFISC Wildland Fire Investigation Subcommittee Approved A fire that is intentional and wrongfully set to burn one's own or someone else's property.
arson task force WFISC Wildland Fire Investigation Subcommittee Approved Group of individuals convened to analyze, investigate and solve arson problems in a particular region.
arsonist WFISC Wildland Fire Investigation Subcommittee Approved One who commits arson.
arteriosclerotic EMC Emergency Medical Committee Approved A chronic disease characterized by abnormal thickening and hardening of the arterial walls with resulting loss of elasticity.
aspect FDSC Fire Danger Subcommittee Approved Cardinal direction toward which a slope faces.
aspect code (Point of Origin) (POO) GSC Geospatial Subcommittee Approved A code used to describe the direction toward which the predominant slope faces at the point of origin of the fire (including ridgetops and/or flat ground). Point of origin is the location where a competent ignition source came into contact with the material first ignited and sustained combustion occurred.
aspirate [foam] ETC Equipment Technology Committee Approved To draw in gases (or other substances); nozzle aspirating systems draw air into the nozzle to mix with the foam solution.
assessment [decision-making] IBC Incident Business Committee Approved The evaluation and interpretation of measurements, intelligence, and other information to provide a basis for decision-making.
assessment [fire weather] FWS Fire Weather Subcommittee Approved A fire weather fire danger product based on a thorough evaluation of all pertinent sources of meteorological, fire danger and resource information.
assigned resources NIMSIC National Incident Management System Integration Committee Approved Resources checked in and assigned work tasks on an incident.
assignments NIMSIC National Incident Management System Integration Committee Approved A task given to a person or team to perform based on operational objectives defined in the IAP.
assistant NIMSIC National Incident Management System Integration Committee Approved A title for subordinates of principal Command Staff and EOC director’s staff positions. The title indicates a level of technical capability, qualification, and responsibility subordinate to the primary positions. Assistants may also be assigned to unit leaders.
assisting agency IBC Incident Business Committee, NIMSIC National Incident Management System Integration Committee Approved An agency or organization providing personnel, services, or other resources to the agency with direct responsibility for incident management.
assumption WFISC Wildland Fire Investigation Subcommittee Approved Acceptance of information as true without proof or demonstration.
asynchronous (training) TDC Training Delivery Committee Approved Training where the students and/or instructors are not interacting with each other in real time. Typically, the students are accessing learning resources at a time of their choosing.
at incident NCSC National Coordination System Committee Proposed New The resource is committed and at the assigned incident.
atmometer FENC Fire Environment Committee Approved An instrument that provides an approximate measure of evapotranspiration by measuring the water loss from an artificial evaporating surface.
atmospheric inversion FWS Fire Weather Subcommittee Approved According to the American Meteorological Society, a departure from the usual decrease or increase with altitude of the value of an atmospheric property; also, the layer through which this departure occurs (the "inversion layer"), or the lowest altitude at which the departure is found ("the base of the inversion"). In fire management usage, nearly always refers to an increase in temperature with increasing height.
atmospheric pressure FWS Fire Weather Subcommittee Approved According to the American Meteorological Society, the net force per unit area exerted by the atmosphere as a consequence of gravitational attraction exerted upon the column of air lying directly above the point in question.  Atmospheric pressure is independent of the orientation of the surface on which it acts.
atmospheric stability FWS Fire Weather Subcommittee Approved According to the American Meteorological Society, the ability of the atmosphere at rest to become turbulent or laminar due to the effects of buoyancy. Air tending to become or remain turbulent is said to be statically unstable; one tending to become or remain laminar is statically stable; and one on the borderline between the two (which might remain laminar or turbulent depending on its history) is statically neutral.
attack a fire IOSC Incident Operations Subcommittee Approved Limit the spread of fire by any appropriate means.
attack line IOSC Incident Operations Subcommittee Approved A line of hose, preconnected to the pump of a fire apparatus and ready for immediate use in attacking a fire. Contrasted to supply lines connecting a water supply with a pump or to feeder lines extended from a pump to various points around the perimeter of a fire. 
attack time IOSC Incident Operations Subcommittee Approved The starting date, hour, and minute of the first suppression work on a fire.
attack unit IOSC Incident Operations Subcommittee Approved Single vehicle or aircraft and its associated personnel and material provided for the purpose of responding to and abating a fire or other emergency.
attack unit response IOSC Incident Operations Subcommittee Approved The response of one attack unit to a fire or other emergency with no regard for the number of return trips to that same fire or emergency.
attainment area FUSC Fire Use Subcommittee Approved An area considered to have air quality as good as, or better than, the National Ambient Air Quality Standards (NAAQS) as defined in the Clean Air Act. An area may be in attainment for one or more pollutants but be in nonattainment for one or more other pollutants. 
authority having jurisdiction NIMSIC National Incident Management System Integration Committee Approved An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure.
authorized passenger NIAC National Interagency Aviation Committee Approved Passengers may be transported in government aircraft only if they meet definition of an Official or an Unofficial Passenger.
Automatic Weather Station (AWS) FDSC Fire Danger Subcommittee Approved A non-GOES telemetered weather station that provides hourly observations to a local database.
automatically regulated IABS Interagency Airtanker Base Subcommittee Approved A proportioning method or device that readily adjusts to changes in water flow and or pressure to maintain a desired mix ratio.
autorotation NIAC National Interagency Aviation Committee Approved A helicopter flight condition in which the lifting rotor is driven entirely by action of air when the helicopter is in motion.
auxiliary pump ETC Equipment Technology Committee Approved A secondary pump on an engine in addition to the main pump. Usually of small capacity.
available Proposed New The resource can be used to fill a request. Resources on preposition incidents qualify as available.
available fuel FUSC Fire Use Subcommittee Approved That portion of the total fuel that would actually burn under various environmental conditions.
available resources NIMSIC National Incident Management System Integration Committee Approved Resources assigned to an incident and available for assignment.
average annual precipitation FDSC Fire Danger Subcommittee Approved The expected amount of annual rainfall. Average annual precipitation is an important component to determining the Keech-Bryam Drought Index (KBDI).
average relative humidity FDSC Fire Danger Subcommittee Approved The mathematical average of the maximum and minimum relative humidities measured at a fire weather station from one basic observation time to the next.
average temperature FWS Fire Weather Subcommittee Approved According to the American Meteorological Society, the average temperature of the air as indicated by a properly exposed thermometer during a given time period, usually a day, a month, or a year.
aviation activity point GSC Geospatial Subcommittee, NIAC National Interagency Aviation Committee Approved A geospatial layer reference to activities that that may present a hazard to pilots during aviation operations displayed as a point.
aviation activity polygon GSC Geospatial Subcommittee, NIAC National Interagency Aviation Committee Approved A geospatial layer reference to activities that that may present a hazard to pilots during aviation operations displayed as a polygon.
aviation call sign NIAC National Interagency Aviation Committee Approved Communication call sign assigned as a unique identifier to an aircraft.
aviation obstruction line GSC Geospatial Subcommittee, NIAC National Interagency Aviation Committee Approved A geospatial reference to physical features that may present a hazard to pilots during aviation operations displayed as a line.
aviation obstruction point GSC Geospatial Subcommittee, NIAC National Interagency Aviation Committee Approved A geospatial reference to physical features that may present a hazard to pilots during aviation operations displayed as a point.
aviation obstruction polygon GSC Geospatial Subcommittee, NIAC National Interagency Aviation Committee Approved A geospatial reference to physical features that may present a hazard to pilots during aviation operations displayed as a polygon.
avoidance FUSC Fire Use Subcommittee Approved A smoke emission control strategy that considers meteorological conditions when scheduling prescribed fires in order to avoid incursions into smoke sensitive areas.
awareness IOSC Incident Operations Subcommittee Archived The continual process of collecting, analyzing, and disseminating intelligence, information, and knowledge to allow organizations and individuals to anticipate requirements and to react effectively and safely.
azimuth [measurement technique] WFISC Wildland Fire Investigation Subcommittee Approved Horizontal angle or bearing of a point measured clockwise from true (astronomic) north.
azimuth circle IOSC Incident Operations Subcommittee Archived A circle graduated in 360 degrees in a clockwise direction from true (astronomic) north.
back azimuth IOSC Incident Operations Subcommittee Archived Angle or bearing 180 degrees opposite of azimuth.
back bearing External Source Approved A back bearing is measured from the object to your position. It is the exact opposite of a direct bearing.
backburn FUSC Fire Use Subcommittee Approved Used in some localities to specify fire set to spread against the wind in prescribed burning.
backdraft FUSC Fire Use Subcommittee Approved Instantaneous explosion or rapid burning of superheated gases that occurs when oxygen is introduced into an oxygen-depleted confined space. It may occur because of inadequate or improper ventilation procedures.
backfire FUSC Fire Use Subcommittee Approved A fire set along the inner edge of a fireline to consume the fuel in the path of a wildfire or change the direction of force of the fire's convection column.
backfire torch ETC Equipment Technology Committee Approved A flame generating device (e.g., a fount containing diesel oil or kerosene and a wick, or a backpack pump serving a flame-jet).
backfiring FUSC Fire Use Subcommittee Approved A tactic associated with indirect attack, intentionally setting fire to fuels inside the control line to slow, knock down, or contain a rapidly spreading fire. Backfiring provides a wide defense perimeter and may be further employed to change the force of the convection column. Backfiring makes possible a strategy of locating control lines at places where the fire can be fought on the firefighter's terms. Except for rare circumstance meeting specified criteria, backfiring is executed on a command decision made through line channels of authority. 
background level FUSC Fire Use Subcommittee Approved In air pollution control, the concentration of air pollutants in a definite area during a fixed period of time prior to the starting up, or the stoppage, of a source of emission under control. In toxic substances monitoring, the average presence in the environment, originally referring to naturally-occurring phenomena. 
backing MFES Mobile Fire Equipment Subcommittee Approved A layer or rubber material used to provide adhesion between the inner tube and the outer jacket.
backing fire FUSC Fire Use Subcommittee, WFISC Wildland Fire Investigation Subcommittee Approved That portion of the fire with slower rates of fire spread and lower intensity normally moving into the wind and/or down slope.
backing fire [spread] FUSC Fire Use Subcommittee, WFISC Wildland Fire Investigation Subcommittee Approved Fire spreading, or ignited to spread, into (against) the wind or downslope. A fire spreading on level ground in the absence of wind is a backing fire.
backing wind FWS Fire Weather Subcommittee Approved According to the American Meteorological Society, in the Northern Hemisphere, a wind that rotates in the counterclockwise direction with increasing height. In fire management usage, in the Northern Hemisphere, a wind that rotates in the counterclockwise direction over a given time period (normally a few hours).
backpack pump ETC Equipment Technology Committee Approved A portable sprayer with hand-pump, fed from a liquid filled container fitted with straps, used mainly in fire and pest control.
baffle NIAC National Interagency Aviation Committee, ETC Equipment Technology Committee Approved A partitioned wall placed in vehicular or aircraft water tanks to reduce shifting of the water load when starting, stopping or turning.
ball valve ETC Equipment Technology Committee Approved A valve in which fluid flow is controlled by a ball with a hole drilled through it. In one position, fluid flows through the hole. When the valve is turned 90 degrees (1/4 turn) the hole is perpendicular to the flow and the ball stops the flow. Intermediate valve positions can be used to adjust the flow. 
Bambi Bucket NIAC National Interagency Aviation Committee Approved A collapsible bucket slung below a helicopter. Used to dip water from a variety of sources for fire suppression.
bandwidth RSUSC Wildland Fire Radio Standards and Use Committee Approved The efficiency technology of either 25 KHz or 12.5 KHz in the frequency bands within the UHF/VHF ranges.
banking snags IOSC Incident Operations Subcommittee Approved The act of throwing mineral soil about the base of an unlighted snag to prevent its being ignited by a surface fire.
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NWCG Latest Announcements

ETC Equipment Bulletin: 25-004 NEW Aquatic Invasive Species – Golden Mussels

Date: July 29, 2025
Questions?  Please contact:
Equipment Technology Committee
 

The Equipment Technology Committee (ETC) issued Equipment Bulletin: 25-004, notifying the wildland fire community about a newly discovered invasive species and actions to take if found. Golden mussels, a highly invasive species recently identified in California, pose a significant risk to native ecosystems, infrastructure, and fire equipment. These mussels rapidly colonize hard and soft surfaces, including aquatic plants and fire equipment, clogging pipes, fouling motors, disrupting water systems, and impacting native species.

To help prevent their spread, fire personnel must follow the decontamination procedures outlined in the NWCG Guide to Preventing Aquatic Invasive Species Transport by Wildland Fire Operations, PMS 444. Additionally, report any sightings immediately to your Lead Resource Advisor and include clear, close-up photos and location details.

Read the complete ETC Equipment Bulletin: 25-004 to learn more. 

References:

NWCG Alerts

ETC Equipment Bulletin: 25-004

NWCG Guide to Preventing Aquatic Invasive Species Transport by Wildland Fire Operations, PMS 444

Incident Position Standards and the Next Generation Position Task Books Now Available for ICT5 and FFT1

Date: July 29, 2025
Questions?  Please contact:
Incident Command Subcommittee
Incident Operations Subcommittee

NWCG is excited to announce that Incident Position Standards and the Next Generation Position Task Books are now available for Incident Commander Type 5 (ICT5) and Firefighter Type 1 Squad Boss (FFT1).

The Performance Support Packages for these positions were developed as part of the Incident Performance and Training Modernization effort. These resources support trainees, qualified personnel, and evaluators in their respective roles.

Any changes to qualification pathways will take effect with the next update of the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1, scheduled for January 2026.

References:

NWCG Incident Commander Type 5 Position Page

NWCG Firefighter Type 1 Squad Boss Position Page

Incident Position Standards and the Next Generation Position Task Books Now Available for ATBM and FWBM

Date: July 28, 2025
Questions?  Please contact:
Airtanker Base Operations Unit

NWCG is excited to announce that Incident Position Standards and the Next Generation Position Task Books are now available for Airtanker Base Manager (ATBM) and Fixed Wing Base Manager (FWBM).

The Performance Support Packages for these positions were developed as part of the Incident Performance and Training Modernization effort. These resources support trainees, qualified personnel, and evaluators in their respective roles.

Any changes to qualification pathways will take effect with the next update of the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1, scheduled for January 2026.

References:

NWCG Airtanker Base Manager Position Page

NWCG Fixed Wing Base Manager Position Page

Incident Position Standards and the Next Generation Position Task Books Now Available for PROC and TIME

Date: July 17, 2025
Questions?  Please contact:
Incident Business Committee

NWCG is excited to announce that Incident Position Standards and the Next Generation Position Task Books are now available for Procurement Unit Leader (PROC) and Time Unit Leader (TIME).

The Performance Support Packages for these positions were developed as part of the Incident Performance and Training Modernization (IPTM) effort. These resources support trainees, qualified personnel, and evaluators in their respective roles.

Any changes to qualification pathways will take effect with the next update of the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1 update, scheduled for January 2026.

References:

NWCG Procurement Unit Leader Position Page

NWCG Time Unit Leader Position Page