NWCG Glossary of Wildland Fire Terminology

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Identification Run

Dry run over the target area by the leadplane to indicate an airtanker's flight path and target, while the air tanker pilot is observing.

Igniter

A pyrotechnic device specifically designed to initiate burning of a fuel mixture or propellant.

Ignition Component

Part of the National Fire Danger Rating System (NFDRS). A rating of the probability that a firebrand will cause an actionable fire.

Ignition Energy

Quantity of heat or electrical energy that must be absorbed by a substance to ignite and burn.

Ignition Factor

The conditions, subsequent actions, and sequence of events that bring a competent ignition source into contact with the materials first ignited. Also referred to as the cause of the fire.

Ignition Method

The means by which a fire is ignited, such as hand-held drip torch, helitorch, and backpack propane tanks.

Ignition Pattern

Manner in which a prescribed fire is ignited. The distance between ignition lines or points and the sequence of igniting them is determined by weather, fuel, topography, firing technique, and other factors which influence fire behavior and fire effects.

Ignition Probability

Chance that a firebrand will cause an ignition when it lands on receptive fuels. (Syn. IGNITION INDEX)

Ignition Time

Time between application of an ignition source and self-sustained combustion of a fuel.

Ignition Trigger

A causative agent for wildland fire. For example, human or lightning.)

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IMI Interactivity Levels

Standards to which IMI products are developed conforming to interactivity level(s) which are appropriate for the instructional design, strategy, media, content, and course specifications.

IMI Level 1 Interactivity

This is the lowest level of courseware development. It is normally a knowledge familiarity lesson, provided in a linear format (one idea after another). Use Level 1 to introduce an idea or concept, or to familiarize. Provide minimal interactivity by using selectable screen icons that are inserted into the linear, or almost linear, flow of the courseware. Allow the student little or no control of the sequence of instructional media presented, including: simple developed graphics, clip art, customer provided video and audio segments (clips). Make use of typical input/output peripherals throughout the lesson.

IMI Level 2 Interactivity

This involves the recall of more information than a level 1 and allows the student more control over the lesson’s scenario through screen icons and other peripherals, such as light pens or touch screens. Typically level 2 is used for non-complex operations and maintenance lessons. Simple emulations or simulations are presented to the user. As an example, the user is requested to rotate switches, turn dials, make adjustments, or identify and replace a faulted component as part of a procedure. This also may include simple to standard developed graphics, and/or clip art, and video and audio clips.

IMI Level 3 Interactivity

This involves the recall of more complex information (compared to levels 1 and 2) and allows the user an increased level of control over the lesson scenario through peripherals such as light pen, touch screen, track ball, or mouse. Video, graphics, or a combination of both is presented simulating the operation of a system, subsystem, or equipment to the user. The lesson scenario training material typically is complex and involves more frequent use of peripherals to affect a transfer of learning. Operation and maintenance procedures are normally practiced with level 3 scenarios and students may be required to alternate between multiple screens to keep pace with the lesson material. Multiple software branches (two to three levels) and rapid response are provided to support remediation. Emulations and simulations are an integral part of this presentation. This may also include complex developed graphics, and/or clip art, and video and audio clips.

Impeller

Rotating part of a centrifugal pump which imparts energy to the liquid to be moved. For shearing purposes, the impeller is on a rotating shaft within the body of liquid.

Implementation Plan

The design and definition of all the activities, resources, limitations, and contingencies required for successful wildland fire management.

Impulse

A term used in weather primarily to describe a weak disturbance that does not necessarily have an associated storm center or surface low. The disturbance usually does not create severe weather and is frequently associated with a marine air push.

Incendiary

A burning compound or metal used to produce intense heat or flame, like a bomb.

Incendiary Device

Contrivance designed and used to start a fire.

Incendiary Fire

A fire that is deliberately ignited under circumstances in which the person knows that the fire should not be ignited. An incendiary fire is not necessarily a fire that meets the legal definition of an arson fire.

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Incident

An occurrence either human-caused or natural phenomenon, that requires action or support by emergency service personnel to prevent or minimize loss of life or damage to property and/or natural resources.

Incident Action Plan (IAP)

Contains objectives reflecting the overall incident strategy and specific tactical actions and supporting information for the next operational period. The plan may be oral or written. When written, the plan may have a number of attachments, including: incident objectives, organization assignment list, division assignment, incident radio communication plan, medical plan, traffic plan, safety plan, and incident map. Formerly called shift plan.

see also: Action Plan

Incident Base

Location at the incident where the primary logistics functions are coordinated and administered. (Incident name or other designator will be added to the term Base.) The incident command post may be collocated with the base. There is only one Base per incident.

Incident Business Advisor (IBA)

Liaison and advisor to the Agency Administrator or Area Commander and works directly for the Agency Administrator or Area Commander. Serves as a bridge to the Agency Administrator, Incident Management Team, and other incident support functions.

Incident Command Post (ICP)

Location at which primary command functions are executed. The ICP may be collocated with the incident base or other incident facilities.

Incident Command System (ICS)

A standardized on-scene emergency management concept specifically designed to allow its user(s) to adopt an integrated organizational structure equal to the complexity and demands of single or multiple incidents, without being hindered by jurisdictional boundaries.

Incident Commander (ICT1, ICT2, ICT3, ICT4, or ICT5)

This ICS position is responsible for overall management of the incident and reports to the Agency Administrator for the agency having incident jurisdiction. This position may have one or more deputies assigned from the same agency or from an assisting agency(s).

Incident Communications Center

The location of the communications unit and the message center.

Incident Communications Manager (INCM)

This ICS position is responsible for providing incident dispatch services and for receiving and transmitting radio and telephone messages to and among incident assigned personnel and reports to the Communications Unit Leader.

see also: Communications Unit

Incident Communications Technician (COMT)

This ICS position is responsible for the programming, tracking, installation, and maintenance of radio and telephone electronic communication equipment and system design for an incident, and reports to the Communications Unit Leader.

see also: Communications Unit

Incident Management Team

The incident commander and appropriate general and command staff personnel assigned to an incident.

Incident Medical Specialist Assistant (IMSA)

This individual assists the IMS manager in managing the IMS program and provides direct emergency medical and occupational health care to incident personnel according to the protocols of their IMS program. Frequently, this person may manage a remote camp medical unit.

Incident Medical Specialist Manager (IMSM)

This individual manages the IMS program on the incident and works for the medical unit leader (MEDL) if one is present. The IMS may also be a MEDL. This person must have successfully completed IMS assignments as an ISMT and IMSA, and the IMS training within their home region.

Incident Medical Specialist Program

An incident-based program to care for emergent and minor medical as well as common occupational health care problems of incident personnel. This program may be deployed to Type I and Type II incidents. Currently, this program is only available in three regions: Northwest (R6), Northern Rockies (R1) and Alaska (R10). In Alaska, the program is known as the Firemedic.

Incident Medical Specialist Technician (IMST)

This individual provides direct emergency medical and occupational health care to incident personnel according to the protocols of their IMS program and works under the supervision of the IMS manager or IMS assistant.

Incident Meteorologist (IMET)

A specially trained meteorologist who provides site specific weather forecasts and information at an incident. The individual works under the direction of the fire behavior analyst and the planning section chief.

Incident Objectives

Statements of guidance and direction necessary for the selection of appropriate strategy(s), and the tactical direction of resources. Incident objectives are based upon agency administrators direction and constraints. Incident objectives must be achievable and measurable, yet flexible enough to allow for strategic and tactical alternatives.

Incident Organization

Resources, together with a complement of overhead personnel, calculated to be sufficient to provide fire efficient incident management.

Incident Overhead

All supervisory positions described in the Incident Command System.

Incident Qualifications Card

A card issued to persons showing their incident management and trainee qualifications to fill specified fire management positions in an incident management organization.

Incident Support Organization

Includes any off-incident support provided to an incident. Examples would be agency dispatch centers, airports, mobilization centers, etc.

Incident Weather Forecast

A special weather forecast for a specific incident prepared by a meteorologist on site at or near the incident area.

Incident with Potential

Wildland fire-related mishap that results in serious or non-serious injuries involving multiple personnel, near accident (which would have resulted in a serious injury or fatality), or substantial loss of property (less than $250,000). The mishap may be so complex and fraught with operational discrepancies that it has the potential to produce an accident, serious injury, or fatality given a similar environment or set of circumstances that existed at the time of the incident.

see also: Near Miss

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Increaser

Increasing coupling used on hose, pump, or nozzles to permit connection of a larger size of hose.

Increment

Any resource or grouping of resources on which individual status is maintained.

Incremental Drop

Air tanker drop in which tank doors are opened in sequence so that fire retardant cascades somewhat continuously.

Independent Action

Fire suppression activities by other than regular fire suppression organizations or a fire cooperator.

Independent Crown Fire

A fire that advances in the tree crowns alone, not requiring any energy from the surface fire to sustain combustion or movement. Also called running crown fire.

Indicated Airspeed (IAS)

The speed of an aircraft as shown on its pitot static airspeed indicator. Calibrated to reflect standard atmosphere adiabatic compressible flow at sea level, uncorrected for airspeed system errors.

Indicator

Visual remains at a fire scene revealing the fire’s progress and action.

Indicator Categories

Classification of indicators into a variety of categories based on how they are formed and the types of material they are found on.

Indirect Attack

A method of suppression in which the control line is located some considerable distance away from the fire's active edge. Generally done in the case of a fast-spreading or high-intensity fire and to utilize natural or constructed firebreaks or fuelbreaks and favorable breaks in the topography. The intervening fuel is usually backfired; but occasionally the main fire is allowed to burn to the line, depending on conditions.

Indirectly Visible Area

Ground, or the vegetation growing thereon, that is not directly visible to a fixed point lookout but lies at not more than a specified depth (commonly 300 feet, 91 meters) below the lookout's line of sight.

Inductor

A control mechanism that allows a regulated quantity of foam concentrate to be introduced into the main hose line.

Industrial Fire Precaution Level (IFPL)

An application of fire danger rating to support regulation of contractors involved in land management activities for fire prevention purposes in the Pacific Northwest.

Industry Crew

Fire crew composed of mill, forestry, or construction workers.

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Infrared (IR)

A heat detection system used for fire detection, mapping, and hotspot identification.

see also: Thermal Imagery

Infrared Groundlink (IR)

A capability through the use of a special mobile ground station to receive air-to-ground IR imagery at an incident.

Inhibition

Process of extinguishing fire by the use of an agent that interrupts the chemical reactions in the combustion process.

Inhibitor

Any agent which retards a chemical reaction.

Initial Action

The actions taken by the first resources to arrive at a wildfire or wildland fire use incident. Initial actions may be size up, patrolling, monitoring, holding action or aggressive initial attack.

Initial Attack (IA)

A planned response to a wildfire given the wildfire's potential fire behavior. The objective of initial attack is to stop the fire and put it out in a manner consistent with firefighter and public safety and values to be protected.

Initial Attack Crew

Specially trained and equipped fire crew for initial attack on a fire.

Initial Attack Fire (IAF)

Fire that is generally contained by the attack units first dispatched, without a significant augmentation of reinforcements, within two hours after initial attack, and full control is expected within the first burning period.

Initial Attack Incident Commander (IAIC)

The incident commander at the time the first attack forces commence suppression work on a fire.

Initial Response

Resources initially committed to an incident.

Inmate Crew

Any fire crew composed of prison inmates or wards.

Inside Diameter (ID)

The internal diameter of a tube, conductor, or coupling, as distinguished from its OD (Outside Diameter). Fire hose sizes are classified by a nominal internal diameter.

In-stand Wind

Wind speed within a stand at about eye level.

Instrument Flight Rules Conditions (IFR)

Weather conditions below the minimum for flight under Visual Flight Rules and therefore requiring the observance of instruments inside the aircraft for controlling flight; generally considered to be less than 1000' AGL and 3 miles distant.

Instrument Landing System (ILS)

System for airplane landing in which the pilot is guided by radio beams.

Instrument Shelter

Naturally or artificially ventilated structure, constructed to specifications and used to shield weather measuring instruments from direct sunshine and precipitation.

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Interactive Multimedia Instruction (IMI)

A group of predominantly interactive, electronically delivered training. IMI products include instructional software and software management tools used in support of instructional programs. IMI products are teaching and management tools and may be used in combination or individually. Used individually, not all IMI products can be considered interactive, multimedia, or instructional. However, IMI products, when used in combination with one another, are interactive, multimedia, and instructional. IMI technology is one of the primary technologies to be used in distance learning.

see also: IMI Interactivity Levels

Interagency Resources Representative (IARR)

An individual who may be assigned to or requested by an incident to serve as the sending unit's representative to oversee the care and treatment of crews, overhead, and equipment assigned to an incident.

Interchangeable Course

A course developed by an interagency, all-hazard subject matter expert group containing the same learning objectives and content as an NWCG developed course. Interchangeable course do not require equivalency determination by a using agency and may have multiple course codes and/or numbers. These courses will be incorporated into IQCS/IQS and credit will be given for the NWCG course.

Intermittent Smoke

Smoke which becomes visible only at intervals.

Internal Load

Load carried inside the fuselage structure of an aircraft.

Internal Payload

Allowable aircraft cabin load, in pounds, with full fuel and pilot in calm air at standard atmosphere.

Inventoried Resources

Assigned resources which have checked in at the incident.

Inversion

Atmospheric inversion. The departure from the usual increase or decrease with altitude of the value of an atmospheric property. In fire management usage, nearly always refers to an increase in temperature with increasing height.

Iron Pipe Thread (IPT)

A tapered thread standard that is used for connecting various sizes of rigid pipe. This standard may be referred to as tapered iron pipe thread (TIPT), National pipe thread (NPT), iron pipe thread (IPT), or iron pipe standard thread (IPS). With tapered thread, the threads and pipe sealant perform the seal at the connection. This is opposed to straight thread connectors which use a gasket to form the seal.

Island

An unburned area within a fire perimeter.

Isobar

A line connecting points of equal atmospheric pressure on a weather map.

Isotherm

A line connecting points of equal temperature on a weather map.

Isothermal Layer

Layer through which temperature remains constant with elevation.

I-Zone

An area that, in relation to wildland/urban fire, has a set of conditions that provides the opportunity for fire to burn from wildland vegetation to the home/structure ignition zone.

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Jettison

Disposing of cargo, fuel, water or retardant overboard to lighten an aircraft or to improve its stability.

Job Hazard Analysis

A job hazard analysis identifies hazards associated with work projects and worksites, and identifies protective equiment or modified work procedures needed.

Joint Information Center (JIC)

A facility established as the central point of contact for news media and interest parties to coordinate incident information activities at the scene of the incident. Public information officials from all participating federal, state, and local agencies should collocate at the JIC.

Joint Information System (JIS)

A system that integrates incident information and public affairs into a cohesive organization designed to provide consistent, coordinated, timely information during crisis or incident operations.

Jump Spot

Selected landing area for smokejumpers.

Jump Suit

Approved protection suit worn for smokejumping.

Jurisdiction

The range or sphere of authority. Public agencies have jurisdiction at an incident related to their legal responsibilities and authority for incident mitigation. Jurisdictional authority at an incident can be political/geographical (e.g., city, county, state or federal boundary lines), or functional (e.g., police department, health department, etc.).

see also: Multijurisdiction Incident

Jurisdictional Agency

The agency having land and resource management responsibility for a specific geographical or functional area as provided by federal, state or local law.

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Keetch-Byram Drought Index (KBDI)

An estimate (0-800) of the amount of precipitation (in 100ths of inches) needed to bring the top 8 inches of soil back to saturation. A value of 0 is complete saturation of the soil, a value of 800 means 8.00 inches of precipitation would be needed for saturation. In the 1988 version of NFDRS, outputs of KBDI are used to adjust live and dead fuel loadings.

see also: Drought Index

Kindling Point

Lowest temperature at which sustained combustion can be initiated for a specified substance. Also called ignition temperature.

KnockDown

To reduce the flame or heat on the more vigorously burning parts of a fire edge.

Knot

Nautical miles per hour, equal to 1.15 mph.

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National Wildfire Coordinating Group (NWCG)

Glossary of Wildland Fire Terminology

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