NWCG Glossary of Wildland Fire, PMS 205

Progressive method of fireline construction on a wildfire without changing relative positions in the line. Work is begun with a suitable space between workers; whenever one worker overtakes another, all of those ahead move one space forward and resume work on the uncompleted part of the line. The last worker does not move ahead until work is completed in his/her space. Forward progress of the crew is coordinated by a crew boss. 

A fuel complex, defined by volume, type condition, arrangement, and location, that determines the degree of ease of ignition and of resistance to control.

Time of day required to record meteorological data at a fire danger station.

The range of options available for response to a wildfire.

Term used to describe any facility that is used for the coordination of agency or jurisdictional resources in support of one or more incidents.

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.

Thickness of a liquid, the degree to which it resists flow.

Set of computerized FIREMODELS run during fire season at the operations coordination center on preselected locations to indicate possible fire spread from those points for that date.

Indicates that the capability is the primary capability for the equipment or aircraft.

Any strategically located supply of water that is readily available for pumps, tanks, trucks, helicopters, or fire camp use.

A calculated reduction in actual payload to provide a margin of safety.

The mass of particulate matter produced per unit mass of fuel consumed (pounds per ton, grams per kilogram).

Composition of fuel laterally across the landscape.

A line of water, or water and chemical retardant, sprayed along the ground, and which serves as a temporary control line from which to ignite or stop a low-intensity fire.

Aircraft navigational equipment that provides the slant range distance in miles (kilometers) from the aircraft to the VOR (VHF Omnidirectional Radio Range) station to which the DME is tuned, usually at or near an airport.

The agency official at the home unit who is responsible for authorizing and granting position certification per agency policy. The agency official is responsible for completing the agency certification block located on the inside front cover of a Position Task Book. 

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. 

In fire suppression terminology, a fire spreading from any fire originally ignited to clear land or burn rubbish, garbage, crop stubble, or meadows (excluding incendiary fires).

Facilities Unit staff set up, maintain, and demobilize all facilities used in support of incident operations. This staff provides facility maintenance and law enforcement/security services needed for incident support. Facilities Unit staff set up the Incident Command Post (ICP), Incident Base, and camps (including trailers or other forms of shelter in and around the incident area) and ensure the maintenance of those facilities. This unit’s staff provide and maintain personnel support facilities, including areas for eating, sleeping, sanitation and showers, and staging. Staff in this unit order additional support items such as portable toilets, shower facilities, and lighting units through the Supply Unit.

Systematic process to comprehend the nature of risk, express and evaluate risk, with the available knowledge.

An extremely dense surface fog (water droplets suspended in the atmosphere) at the site of combustion that reduces visibility to less than three meters (ten feet).

The organizational level having functional or geographical responsibility for major aspects of incident operations. A Branch falls between the Section Chief and the division or group in the Operations Section, and between the section and units in the Logistics Section. Branches are identified by Roman numerals or by functional area.

The strategy employed in appropriate management responses where a fire perimeter is managed by a combination of direct and indirect actions and use of natural topographic features, fuel, and weather factors.

Fire hose with a smooth inner coating of rubber or plastic to reduce friction loss.

A fire in which a solid flame develops in the crowns of trees, but the surface and crown phases advance as a linked unit dependent on each other.

According to the American Meteorological Society, the layer of air near a boundary that is affected by friction against that boundary surface, and possibly by transport of heat and other variables across that surface.

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.

The hours of a day (a daily tour-of-duty) and the days of an administrative workweek (a weekly tour-of-duty) that constitutes an employee's regularly scheduled administrative workweek.

Of, or pertaining to, measurement by weight.

Management of wildfire or prescribed fire to meet resource objectives specified in land/resource management plans.

Apparatus utilizing an air compressor and positive displacement pump coupled to the same engine, plumbed to a non-pressurized tank, for producing foam. The operation involves injecting compressed air into a liquid stream containing a suitable foaming agent.

A tube, constructed with deflectors or baffles, that mixes foam solution and air to produce tiny, uniform bubbles in a short distance (1 to 2 ft).

Values of one or more fire weather/fire danger indexes that have been statistically related to occurrence of fires (fire business). Generally the threshold is a value, or range of values where historical fire activity has significantly increased or decreased. 

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. 

A plant that does not develop woody, persistent tissue but is relatively soft or succulent and sprouts from the base (perennials) or develops from seed (annuals) each year. Includes grasses, forbs and ferns.

Any method or pattern of igniting a wildland area to consume the fuel in a prescribed pattern. E.g., heading or backing fire, spot fire, strip-head fire, and ring fire.

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.

General term for two or more firefighters organized to work as a unit.

The ordered movement of a resource or resources to an assigned operational mission, or an administrative move from one location to another.

A force created by the rapid acceleration or deceleration of water, commonly created by opening or closing a valve too quickly. Pressures developed in a water hammer, proportional to the mass multiplied by the square of the velocity, can damage a pipe or hose. 

The intermingling of plant communities and their successional stages in such a manner as to give the impression of an interwoven design.

Pollutants deemed most harmful to public health and welfare and that can be monitored effectively. They include carbon monoxide (CO), lead (Pb), nitrogen oxides (Nox), sulfur dioxide (SO2), ozone (O3), particulate matter (PM) of aerodynamic diameter less than or equal to 10 micrometers (PM10) and particulate matter of aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5). 

A fire burning in vegetation that is predominantly shrubs, brush, and scrub growth.

A signaling device mounted on retardant aircraft which generates a tremulous siren sound to warn firefighters on the ground that a plane is approaching to drop retardant.

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.

A group of ICS-qualified personnel consisting of an Incident Commander, Command and General Staff, and personnel assigned to other key ICS positions.

Any liquid or solid particles. "Total suspended particulates", as used in air quality, are those particles suspended in or falling through the atmosphere. They generally range in size (diameter) from 0.1 to 100 micrometers.

Objects that are easily susceptible to damage from head and flame and can be easily damaged or destroyed by suppression action and/or during the evidence collection process. E.g., cigarette ash.

A ridge of soil and debris along the outside edge of a fireline, resulting from line construction.

Describes how strongly a fire investigator holds an opinion or conclusion, includes two levels, Possible and Probable.