NWCG Glossary of Wildland Fire, PMS 205

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). 

Total time a fuel can burn and continue to feed energy to the base of a forward-traveling convection column.

The process in which teams of professional and peer counselors provide emotional and psychological support to incident personnel who are or have been involved in a critical (highly stressful) incident.

Intersecting lines of sight from two points to the same object, frequently used to determine location of a fire from lookouts.

Combustion of the twigs, and needles or leaves of a tree during a fire.

The ground area covered by the crown of a tree as delimited by the vertical projection of its outermost perimeter.

A fire that advances from top to top of trees or shrubs more or less independent of a surface fire. Crown fires are sometimes classed as running or dependent to distinguish the degree of independence from the surface fire.

A theoretical concept that is used to model and classify crown fire. It may be observable after the fact in burn severity assessments.

A fire that rises from ground into the tree crowns and advances from tree top to tree top. To intermittently ignite tree crowns as a surface fire advances.

The ratio of live crown to tree height.

Browning of needles or leaves in the crown of a tree or shrub caused by heating to lethal temperature during a fire. Crown scorch may not be apparent for several weeks after the fire.

The height above the surface of the ground to which a tree canopy is scorched.

A probability that a crown fire may start, calculated from inputs of foliage moisture content and height of the lowest part of the tree crowns above the surface.

The ultimate growth of a cumulus cloud into an anvil-shaped cloud with considerable vertical development, usually with fibrous ice crystal tops, and usually accompanied by lightning, thunder, hail, and strong winds.

A principal low cloud type in the form of individual cauliflower-like cells of sharp non-fibrous outline and less vertical development than cumulonimbus.

A fireline trench on the downhill side of fire burning on steep slopes that is supposed to be built deep enough to catch rolling firebrands that could otherwise start fire below the fireline. A high berm on the outermost downhill side of the trench helps the cup trench catch material.

Weight of a truck empty (without payload and driver) but ready to drive, including a full fuel tank, cooling system, crankcase, tools, spare wheel, and all other equipment specified as standard.

In the 1978 version of NFDRS, the herbaceous stage when herbaceous fuel moisture falls to 30% or less.

In fire danger rating, a subjective estimate of the degree of activity of a potential human-caused fire source relative to that which is normally experienced. Five activity levels are defined: none, low, normal, high, and extreme.

Paid on a calendar day basis (0001-2400).

The comparative differences of damage to objects resulting from the fire’s passage.

The amount of fire related destruction to combustible objects determined by comparing opposing sides of an object.

A particular day of a calendar year.

The last edit, update, of this GIS record

The combination of date and time elements.

Fuels with no living tissue in which moisture content is governed almost entirely by absorption or evaporation of atmospheric moisture (relative humidity and precipitation).

In prescribed fire terminology, a fire used to dispose of scattered, piled, or windrowed dead woody fuel, generally in the absence of a merchantable overstory. Its purpose is to reduce unsightly fuel concentrations, or consume unwanted natural fuels to facilitate subsequent resource management or land use actions on the area. 

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).

The helibase operational area that includes the touchdown pad, safety circle, hover lanes, and external cargo transport area.

A fire that has gained headway and built up heat in a structure so as to require greater cooling for extinguishment.

A fire burning far below the surface in duff, mulch, peat, or other combustibles as contrasted with a surface fire.

As it refers to atmospheric pressure, a decrease in the central pressure of a low. This is usually accompanied by intensification of the cyclonic circulation (counter-clockwise wind flow around the low).

A burning with great heat and intense light.

Chemical decomposition by burning material in which the reaction is less than sonic velocity, for example, low explosives.

In a discussion of fire retardant slurries, deterioration of viscosity.

Polystyrene balls, 1.25 inches in diameter, containing potassium permanganate. The balls are fed into a dispenser, generally mounted in a helicopter, where they are injected with a water-glycol solution and then drop through a chute leading out of the helicopter. The chemicals react thermally and ignite in 25-30 seconds. The space between ignition points on the ground is primarily a function of helicopter speed, gear ratio of the dispenser, and the number of chutes used (up to four). 

A statement provided to the incident commander by the agency administrator delegating authority and assigning responsibility. The delegation of authority can include objectives, priorities, expectations, constraints and other considerations or guidelines as needed.

The orderly, safe, and efficient return of an incident resource to its original location and status.

Demobilization Unit staff develop an Incident Demobilization Plan that includes specific instructions for all personnel and other resources to be demobilized. They begin their work early in the incident, creating rosters of personnel and resources and obtaining any missing information as check-in proceeds. Once the Incident Commander or Unified Command has approved the Incident Demobilization Plan, Demobilization Unit staff ensure its distribution at the incident and elsewhere, as necessary. For major incidents, demobilization plans are dynamic and the staff in the Demobilization Unit may need to update them frequently.

A layer of clouds whose ratio of dense sky cover to total sky cover is more than one-half.

Sky cover that prevents detection of higher clouds or the sky above it.

The ratio of the original volume of the nonaerated foam solution to the resultant volume of foam. The inverse of expansion.

Above Agency in hierarchy.

Day/Month/Year officially accepted by the Department as meeting all Department requirements to receive funds in the planned year.

An NDVI-derived image of vegetation greenness compared to its average greenness for the current week of the year.

The reduction in forest floor thickness due to consumption by fire.

Sometimes referred to as "alligatoring", where combustible material appears to have a fissured or scaly appearance similar to an alligator's hide. Most commonly associated with finished lumber products, such as boards and fence posts.

A fully qualified individual who, in the absence of a superior, can be delegated the authority to manage a functional operation or to perform a specific task. In some cases, a deputy can act as relief for a superior, and, therefore, should be fully qualified in the position. Deputies generally can be assigned to the Incident Commander, EOC director, General Staff, and branch directors.