NWCG Glossary of Wildland Fire (PMS 205)

In the context of wildland fire, a prescription is measurable criteria that define conditions under which a prescribed fire may be ignited. Prescriptions may also be used to guide selection of management responses to wildfire to define conditions under which management actions are most likely to achieve incident management objectives. Prescription criteria typically describe environmental conditions such as temperature, humidity and fuel moisture, but may also include safety, economic, public health, geographic, administrative, social, or legal considerations. 

The difference in atmospheric pressure between two points on a weather map. That is, the magnitude of pressure difference between two points at sea level, or at constant elevation above sea level. Wind speed is directly related to pressure gradient. If distance between constant pressure lines is reduced by one-half, wind speed will be doubled. Conversely, if distance between lines is doubled, wind speed will be reduced by one-half. 

Reduction in water pressure between a pump or hydrant and a nozzle due to expenditure of pressure energy required to move water through a hose; includes losses due to back pressure, friction loss, elevation loss, and/or losses in fittings.

The distribution of surface atmospheric pressure features over an area of the earth as shown on a weather map. Surface pressure features include lines of constant pressure (isobars), highs, lows, and pressure gradient. The pressure pattern is directly related to wind speeds and directions at specific locations. 

Activities in advance of fire occurrence to ensure effective suppression action. Includes planning the organization, recruiting and training, procuring equipment and supplies, maintaining fire equipment and fire control improvements, and negotiating cooperative and/or mutual aid agreements. 

The use of water, foam or retardant along a control line in advance of the fire. Often used where ground cover or terrain is considered best for control action.

Activities directed at reducing the incidence of human-caused wildfires, including public education, law enforcement, personal contact, and other actions taken to reduce ignitions.

A program identified by the Clean Air Act to prevent air quality and visibility degradation and to remedy existing visibility problems. Areas of the country are grouped into 3 classes which are allowed certain degrees of pollution depending on their uses. National Parks and Wilderness Areas meeting certain criteria are "Class I" or "clean area" in that they have the smallest allowable increment of degradation. 

Provides support to fire prevention and wildland fire educational needs preceding and during periods of high wildland fire danger or prescribed fire activity. The teams provide assistance to wildland fire managers with coordination of fire loss mitigation efforts with public, state or local agencies.

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

Individual’s primary email

A lookout point that must be staffed to meet planned minimum seen area coverage in a given locality. For that reason, continuous service is necessary during the normal fire season and the lookout (person) is not sent to fires.

Individual’s primary phone.

The six-digit National Weather Station ID for the National Fire Danger Rating System (NFDRS) weather station that best represents the predominate weather and climate conditions for the incident site at the time of initial response.

Filling pump with water when pump is taking water not under a pressure head. Necessary for centrifugal pumps.

An imaginary line on the ground running north-south which is accurately laid out to serve as the reference meridianin land surveys.

A number representing the chance that a given event will occur. The range is from 0% for an impossible event, to 100% for an inevitable event.

A forecast of the probability of occurrence of one or more of a mutually exclusive set of weather contingencies as distinguished from a series of categorical statements.

The chance that a firebrand will cause an ignition when it lands on receptive fuels.

A level of certainty corresponding to being more likely true than not.

Agency personnel with specific delegation of procurement authority, acting within the limits of agency policy of said authority.

Functional unit within the Finance/Administration Section responsible for managing all financial matters pertaining to vendor contracts.

An event dealing with maintenance of licenses, currencies, or proficiencies, including recurring proficiencies.

A hose lay in which double shutoff wye (Y) valves are inserted in the main line at intervals and lateral lines are run from the wyes to the fire edge, thus permitting continuous application of water during extension of the lay.

A system of organizing workers to build fireline in which they advance without changing relative positions in line.

Allows identification of an activity which is unlawful or otherwise prohibited (burn ban, unpermitted, etc.) by local authorities.

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

Equivalent to Fire Name.

The specific results expected from completing a project.

An estimate of the direction in which the incident is expected to spread, migrate, or expand within a specified time frame.

A device that adds a predetermined amount of foam concentrate to water to form foam solution.

Areas for which a fire protection organization has the primary responsibility for managing a wildfire and directing fire management actions. Such responsibility may be authorized by law, contract, or personal interest of the firefighting agent (e.g., a lumber operator). Note: Several agencies or entities may have some basic responsibilities (e.g., private owner) without being known as the fire organization having primary responsibility.

The side of an object opposite the oncoming fire and therefore shielded from the oncoming fire by the object itself.

The entity responsible for providing direct incident management and services to a given area pursuant to its jurisdictional responsibility or as specified by law, contract or agreement.

A geographical area which is administratively defined and for which organized fire suppression activities are formally planned.

That area for which a particular fire protection organization has the primary responsibility for attacking an uncontrolled fire and for directing the suppression action. Such responsibility may develop through law, contract, or personal interest of the firefighting agent (e.g., a lumber operator). Several agencies or entities may have some basic responsibilities (e.g., private owner) without being known as the fire organization having direct protection responsibility. 

The exterior perimeter of an area within which a specified fire agency has assumed a degree of responsibility for wildland fire control. It may include land in addition to that for which the agency has jurisdiction or contractual responsibility.

Any government organization that is a source of resources for response or mutual aid support to an incident, whether in the field, at the scene of an incident, or operations center.  This includes government organizations that administer contracts or agreements for resources.

General name for instruments designed to determine the moisture content of air. A psychrometer consists of dry- and wet-bulb thermometers that give the dry- and wet-bulb temperatures, which in turn are used to determine relative humidity and dew point.

Aircraft used only in the service of a government or a political subdivision. It does not include any government-owned aircraft engaged in carrying persons for commercial purposes.

A community or public service event, managed by an organization external to the fire community, which requires resource support from the fire community. This category includes VIP visits, law enforcement activities, concerts, conventions, parades, road/bridge closures, etc.

An event managed by local public service organizations (police, fire, law enforcement, emergency medical services, or military).

A combination chopping and trenching tool widely used in fireline construction, which combines a single-bitted axe blade with a narrow adze-like trenching blade fitted to a straight handle.

Partly decayed material, such as old wood, in which fire can smolder unless it is carefully mopped up and extinguished. A good receptor for firebrands when dry.

The thermal or chemical decomposition of fuel at an elevated temperature. This is the preignition combustion phase of burning during which heat energy is absorbed by the fuel which, in turn, gives off flammable tars, pitches, and gases.

A mixture of chemicals designed to produce heat, light, gas, smoke or noise.