NWCG Glossary of Wildland Fire, PMS 205

This glossary provides the wildland fire community a single source for wildland fire and incident management terminology commonly used by the NWCG and its subgroups.

Glossary entries related to Organizations, IT Applications, and NWCG Positions have been removed from the glossary based on term inclusion criteria. For more information about the glossary and the criteria, see the About the NWCG Glossary page or the NWCG User Guide for the Glossary of Wildland Fire, PMS 937.

Reference Definitions

Some of the terms within this glossary will be followed by initials or will have references or comments at the end of the definition to help broaden the recognition and understanding of the term. An explanation of those references is as follows:

Also called: Means there is another term that may sometimes be in use, but is not defined in this glossary.
Acronym: An abbreviation formed from the initial letters of other words and pronounced as a word. An acronym appears in parentheses following the term.
Initialism: An abbreviation consisting of initial letters pronounced separately. An initialism appears in parentheses following the term.
See: Means there is another, preferred term that should be used instead. In such a case only the preferred term is defined in this glossary.
See Also: Means there are one or more related terms that may also be of interest to the glossary user. The related terms are also defined in this glossary.
Synonym: Means the term is synonymous with another. The terms have the same, or essentially the same, definition and the terms are interchangeable in their use.
Definition Extension: An example, further explanation, or usage guidance in support of the definition.

Glossary Acronyms/Initialisms

6 (1) | A (126) | B (94) | C (160) | D (102) | E (67) | F (261) | G (48) | H (90) | I (83) | J (10) | K (4) | L (74) | M (92) | N (31) | O (47) | P (133) | Q (6) | R (100) | S (221) | T (71) | U (28) | V (37) | W (60) | Z (1)
Ladder Fuels
  • Fuels which provide vertical continuity between strata, thereby allowing fire to carry from surface fuels into the crowns of trees or shrubs with relative ease. They help initiate and assure the continuation of crowning. 
Land Occupancy Fire
  • Fire started as a result of land occupancy for agricultural purposes, industrial establishment, construction, maintenance and use of rights-of-way, and residences, except equipment use and smoking. 
Land Use Plan
  • A set of decisions that establish management direction for land within an administrative area; an assimilation of land-use-plan-level decisions developed through the planning process regardless of the scale at which the decisions were developed. 
Land/Resource Management Plan (L/RMP)
  • A document prepared with public participation and approved by an agency administrator that provides general guidance and direction for land and resource management activities for an administrative area. The L/RMP identifies the need for fire’s role in a particular area and for a specific benefit. The objectives in the L/RMP provide the basis for the development of fire management objectives and the fire management program in the designated area.  Source:  2009 Guidance for Implementation Federal Wildland Fire Management Policy and Fire Management Board Memorandum 19-004a.
  • The person or entity that owns the land or has the authority to convey title to others.
    • Definition Extension: Landowner or Owner are not directly interchangeable with Jurisdictional Unit or Protecting Unit. For example, acres burned may be reported for “private” landownership but “private” would not be identified as a Jurisdictional Unit.
Lapse Rate
  • Change of an atmospheric variable (temperature unless specified otherwise) with height. 
Large Aircraft
  • Aircraft in which maximum certified gross weight at take-off exceeds 12,500 pounds. 
Large Fire
  1. For statistical purposes, a fire burning more than a specified area of land e.g., 300 acres.
  2. A fire burning with a size and intensity such that its behavior is determined by interaction between its own convection column and weather conditions above the surface. 
Large Fire-Day
  • In FireFamily Plus, a day with both a weather observation and at least one large (as defined by the user) fire. 
Lateral Fire
Lead Line
  • Line or set of lines made of rope, webbing, or cable and used in helicopter external load operations; usually placed between a swivel or the cargo hook and the load. 
  • The ICS title for an individual responsible for a task force, strike team, or functional unit. 
Leaders Intent
  • A concise statement that outlines what individuals must know in order to be successful for a given assignment. The intent communicates three essential pieces of information:
    • Task - What is the goal or objective
    • Purpose - Why it is to be done
    • End state - How it should look when successfully completed 
  • The art of providing purpose, direction, and motivation to a group of people in order to accomplish a mission and improve the organization. Leaders provide purpose by clearly communicating their intent and describing the desired end state of an assignment to their followers. Leaders provide direction by maintaining standards of performance for their followers. Leaders provide motivation by setting the example for their followers. 
  • Aircraft with pilot used to make trial runs over the target area to check wind, smoke conditions, topography and to lead airtankers to targets and supervise their drops. 
Leapfrog Method
  • A system of organizing workers in fire suppression in which each crew member is assigned a specific task such as clearing or digging fireline on a specific section of control line, and when that task is completed, passes other workers in moving to a new assignment. 
Learning Content Management System (LCMS)
  • Any system that keeps learner information, can launch and communicate with SCOs, and can interpret instructions that tell it which SCO comes next. 
Learning Objective
  • A description of the intended outcome of a training class, program, or evolution. The learning objective identifies the condition, the task, and the standard to which the student much achieve. 
Learning Objects
  • Reusable learning objects represent an alternative approach to content development. In this approach, content is broken down into chunks. From a pedagogical perspective, each chunk might play a specific role within an instructional design methodology. Such chunks are called learning objects. There is no standard for the size (or granularity) of a learning object. Larger learning objects are typically harder to reuse, and smaller learner objects save less work for those who reuse them. Normally the happy medium has been estimated as between five and fifteen minutes of learning material. The requirements for each chunk are:
    • Each chunk must be able to communicate with learning systems using a standardized method that does not depend on the system.
    • What happens within a chunk is the chunk's business.
    • How a learner moves between chunks is controlled by the learning system.
    • Each chunk must have a description (metadata tag) that enables designers to search for and find the right chunk for the right job. 
Legitimate Smoke
  • Smoke from any authorized use of fire (e.g., locomotive, industrial operations, permitted debris burning). 
Level of Certainty
Level of Service
  • Amount of fire prevention and fire suppression supplied; may be expressed several ways (e.g., percent of people or buildings protected, area protected, dollar value of property protected, firefighters per capita, water flow capability). 
  • Refers to the joint consideration of both the life and physical well-being of individuals. 
Lifting Processes
  • Any of the processes that lead to upward vertical motion in the atmosphere. These processes may include low level convergence, heating or thermal convection, orographic lifting over the mountains, and frontal lifting. 
Light (Fine) Fuels
  • Fast-drying fuels, generally with a comparatively high surface area-to-volume ratio, which are less than 1/4-inch in diameter and have a timelag of 1 hour or less. These fuels readily ignite and are rapidly consumed by fire when dry. 
Light Wind
  • Wind speed less than 7 mph (6 knots) measured at 20 feet above ground. At eye level, light winds are less than 3 mph (3 knots). 
Lightning Activity Level (LAL)
  • Part of the National Fire Danger Rating System (NFDRS). A number, on a scale of 1 to 6, which reflects frequency and character of cloud-to-ground lightning (forecasted or observed). The scale for 1 to 5 is exponential, based on powers of 2 (i.e., LAL 3 indicates twice the lightning of LAL 2). LAL 6 is a special category for dry lightning and is closely equivalent to LAL 3 in strike frequency. 
Lightning Fire
  • Wildfire caused directly or indirectly by lightning. 
Lightning Fire Occurrence Index
  • Part of the National Fire Danger Rating System (NFDRS). Numerical rating of the potential occurrence of lightning-caused fires. 
Lightning Risk (LR)
  • Part of the National Fire Danger Rating System (NFDRS). A number related to the expected number of cloud-to-ground lightning strokes to which a protection unit is expected to be exposed during the rating period. The LR value used in the occurrence index includes an adjustment for lightning activity experienced during the previous day to account for possible holdover fires. 
Lightning Risk Scaling Factor
  • Part of the National Fire Danger Rating System (NFDRS). Factor derived from local thunderstorm and lightning-caused fire records that adjusts predictions of the basic lightning fire occurrence model to local experience, accounting for factors not addressed directly by the model (e.g., susceptibility of local fuels to ignition by lightning, fuel continuity, topography, regional characteristics of thunderstorms). 
Lightning Stroke Counter
  • Electronic sensor used to record the number of lightning strokes within a predetermined range over a specified period of time. 
Lightweight Debris
  • Removing branches from a felled or standing tree, or from brush. 
Limited Containment
  • Halting of fire spread at the head, or that portion of the flanks of a prescribed fire that is threatening to exceed prescription criteria, and ensuring that this spread rate will not be encountered again; does not indicate mopup. 
Line Cutter
  • Fire crew member in the progressive method of line construction who cuts and clears away brush, small saplings, vines, and other obstructions in the path of the fireline; usually equipped with ax or brush hook, or pulaski. 
Line Officer
  • Managing officer, or designee, of the agency, division thereof, or jurisdiction having statutory responsibility for incident mitigation and management. 
Line Scout
  • A firefighter who determines the location of a fire line. 
Lined Fire Hose
  • Fire hose with a smooth inner coating of rubber or plastic to reduce friction loss. 
Liquid Concentrate (LC)
  • Liquid phosphate fertilizers used as fire retardants, usually diluted three to five times prior to application. 
  • The top layer of forest floor, composed of loose debris of dead sticks, branches, twigs, and recently fallen leaves or needles; little altered in structure by decomposition. 
Little Change
  • Insignificant change in wind speed, direction, and temperature (less than 5 degrees) and relative humidity (less than five percent), respectively. When used as a general statement in a long-range forecast, all four criteria apply. 
Live Fuel Moisture Content
  • Ratio of the amount of water to the amount of dry plant material in living plants. 
Live Fuels
  • Living plants, such as trees, grasses, and shrubs, in which the seasonal moisture content cycle is controlled largely by internal physiological mechanisms, rather than by external weather influences. 
Live Herbaceous Moisture Content
  • Ratio of the amount of water to the amount of dry plant material in herbaceous plants (i.e., grasses and forbs). 
Live Line
  • Hose line filled with water under pressure and ready to use. 
Live Reel
  • Hose line or reel on a fire engine, carried preconnected to the pump, ready for use without making connections to pump or attaching nozzle. 
Live Run
  • Indicates that the airtanker has the target in sight and will make a retardant drop on this run over the target. 
Live Woody Moisture Content
  • Ratio of the amount of water to the amount of dry plant material in shrubs. 
Load and Hold
  • An order given to the airtanker pilot to pick up another load of retardant or water and hold at the reload base. The tanker is still committed to the fire. 
Load and Return
  • Order given to the airtanker pilot to pick up another load of fire retardant or water and return to the fire. 
Load Calculation Form
  • An agency form used to calculate helicopter allowable payload. 
Loading Pad
  • Concrete pad at a retardant base on which aircraft stand when being loaded. 
  • Individual responsible to the Deck Coordinator for the manifesting, loading and unloading of personnel, equipment and cargo. 
Local Agency
  • Any agency having jurisdictional responsibility for all or part of an incident. 
Local Resource
  • Resources within a dispatch center's area of responsibility. 
Local Responsibility Area
  • Lands on which neither the state nor the federal government has any legal responsibility for providing fire protection. 
Local Winds
Logging Debris
  • Unwanted tree parts (crowns, logs, uprooted stumps) remaining after harvest. 
Logistics Section
  • The ICS section responsible for providing facilities, services, and supplies in support of an incident. 
Long-Range Forecast
Long-Range Spotting
  • Large glowing firebrands are carried high into the convection column and then fall out downwind beyond the main fire starting new fires. Such spotting can easily occur 1/4 mile or more from the firebrand's source. 
Long-Term Fire Danger
  • The results of those factors in fire danger affecting long-term planning; involves consideration of past records and conditions and probable future trends. 
Long-term Fire Residence
Long-Term Fire Retardant
  • Chemical that inhibits combustion primarily through chemical reactions between products of combustion and the applied chemicals, even after the water component has evaporated. Other chemical effects also may be achieved, such as film-forming and intumescence. 
  • A line or set of lines, usually in 50' increments, used in external load operations that allow the helicopter to place loads in areas in which the helicopter could not safely land. 
  1. A person designated to detect and report fires from a vantage point.
  2. A location from which fires can be detected and reported.
  3. A fire crew member assigned to observe the fire and warn the crew when there is danger of becoming trapped. 
Lookout Tower
  • Structure that elevates a person above nearby obstructions to sight for fires; generally capped by some sort of house or cupola. 
Lookout(s), Communication(s), Escape Route(s), and Safety Zone(s) (LCES) 
  • Elements of a safety system used by fire fighters to routinely assess their current situation with respect to wildland firefighting hazards. 
  • After felling, cutting branches, tops, and unwanted boles into lengths such that resultant logging debris will lie close to the ground. 
Lopping and Scattering
  • Lopping logging debris and spreading it more or less evenly over the ground. 
Lost Line
  • Any part of a fireline rendered useless by a breakover of the fire. 
  • An area of relatively low atmospheric pressure in which winds tend to move in a counterclockwise direction, spiraling in toward the low's center.  Source: http://glossary.ametsoc.org/wiki/Low
Low Expansion
  • Foam with an expansion between 1:1 and 20:1.