NWCG Glossary of Wildland Fire, PMS 205

Hose commonly of cotton, linen, or synthetic fiber construction without rubber tube or lining, often used for wildfires because of its light weight and self protecting (weeping) characteristics; such hose is attached to first-aid standpipes in buildings. At a specified flow, friction loss in unlined hose of a stated diameter is about twice that of lined fire hose. 

Areas for which no fire organization has responsibility for management of a wildfire authorized by law, contract, or personal interest of the fire organization (e.g., a timber or rangeland association). 

Upper Level Disturbance, Cold Low Aloft: A circulation feature of the upper atmosphere where pressure, at a constant altitude, is lowest. Winds blow counter-clockwise around the center in an approximately circular pattern. Upper level lows are usually quite small. The mechanics of these upper lows is such that a pool of cool moist air always accompanies their development. There is often no evidence of low pressure at the earth's surface. An upper low may exist above a surface high pressure system. 

Trough, Trough Aloft, Upper Level [Cold] Low: An elongated area of relatively low pressure, at constant altitude, in the atmosphere. The opposite of an upper level ridge. Upper level troughs are usually oriented north-south with the north end open. That is, air currents moving from west to east around the earth flow around three sides of the trough then turn eastward rather than toward the west, as in the case of a closed circulation. A large upper level trough may have one or more small upper level closed low circulation systems within it. 

Upper High, High Aloft, Upper Level Ridge: A circulation feature of the upper atmosphere where pressure, at a constant altitude, is higher than in the surrounding region. Winds blow clockwise around an upper level high. Air in an upper level high is usually subsiding. This results in comparatively warm dry air with light winds over a large area. An upper level high may exist without there being high pressure at the earth's surface. 

An elongated area of relatively high pressure, at a constant altitude, in the atmosphere. The opposite of an upper level trough. Upper level ridges are often oriented north-south, alternating between upper level troughs, however, during summer they may assume random orientations and vast dimensions. 

An event dealing with a search, and/or rescue, and/or recovery in an urban setting.

The appropriate ratio of liquid foam concentrate to water recommended by the chemical manufacturer for each class of fire, usually expressed as a percent (such as 0.5%).

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

Maximum computed gross weight minus equipped weight of a helicopter.

Characteristics fire cone-shaped pattern left by a fire on a wall, at or near its point of origin.

A stretch of low land lying between hills or mountains which are sometimes occupied by a stream.

The elements of a community or natural area considered valuable by an individual or community that could be negatively impacted by a wildfire or wildfire operations. These values can vary by community and can include diverse characteristics such as homes, specific structures, water supply, power grids, natural and cultural resources, community infrastructure, and other economic, environmental, and social values.

Include property, structures, physical improvements, natural and cultural resources, community infrastructure, and economic, environmental, and social values.

Creating a seal with foam which prevents a release of flammable vapors from fuels.

Any changing characteristic; in statistics, a measurable characteristic of an experimental unit.

A ceiling of less than 3,000 feet (900 m) which rapidly increases or decreases in height by one or more reportable values during the period of observation.

Resultant of all fire danger factors that vary from day to day, month to month, or year to year (e.g., fire weather, fuel moisture content, condition of vegetation, variable risk).

A sky condition that varies between reportable values of sky cover amounts during the period of observation.

A condition when the prevailing visibility is less than 3 miles (5 km) and rapidly increases and decreases by one or more reportable values during the period of observation.

Wind direction which varies by 60 degrees or more during the period of time the wind direction is being determined.

Directions of fire spread as related to rate of spread calculations (in degrees from upslope).

The vegetation departure index is displayed on actuals, and is an index on the FRCC. The vegetation departure percentage is displayed on estimated treatments and activities and is a percentage.

Development of new aboveground plants from surviving plant parts, such as by sprouting from a root crown or rhizomes. Even if plants form their own root system, they are still genetically the same as the parent plant.

Establishment of a new plant from a seed that is a genetically distinct individual.

Fire originating in or on a vehicle or mobile equipment.

An event dealing with a fire originating in or on a vehicle or mobile equipment.

The Vehicle Identification Number (VIN) assigned to a piece of equipment.

The release of enclosed smoke and heat from a structure by creating openings in it, as by hacking a hole in the roof, to allow free passage of air.

A numerical value relating the potential of the atmosphere to disperse airborne pollutants from a stationary source, calculated by multiplying the mixing height by the transport wind speed.

A measure of the volume rate of horizontal transport of air within the mixing layer, per unit distance, normal to the wind. Units are measured in square meters per second or knot-feet.

Fuels above ground and their vertical continuity, which influences fire reaching various levels or vegetation strata.

Plot of the actual dry-bulb temperature against height above the earth's surface, most commonly determined by a RAWINSONDE observation.

Radio frequency range from 30 MHz to 299 MHz. The sub-bands most commonly used by fire are: VHF-FM Lo band: Frequency Modulation 30 MHz - 80 MHz, of which fire frequencies are between 30 MHz and 50 MHz. VHF-FM Hi band: Frequency Modulation 150 MHz - 174 MHz. This is the most widely used band by fire agencies. VHF-AM: Amplitude Modulation. This band is commonly referred to as the "Victor or VHF" band. The frequency range is from 118 MHz to 136 MHz. The only authorized use of this band is for aviation. The FAA controls and assigns all frequencies within this sub-band. 

System of radio navigation in which any magnetic bearing relative to a special radio transmitter on the ground may be chosen and flown by an aircraft pilot.

A subjective assessment of the health of individual plants in similar site and growing conditions; or a more specific measure based upon a specific facet of growth, such as seed stalk or tiller production per plant or per unit area.

Precipitation falling out of a cloud but evaporating before reaching the ground.

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

Water that contains a thickening agent to reduce surface runoff; tends to cling to burning fuels and spread in layers that are several times thicker than plain water, thereby having an increased capacity to absorb heat, cool fuel, and exclude oxygen.

The greatest horizontal distance at which selected objects can be seen and identified, or its equivalent derived from instrumental measurements.

Map showing the different classes of visible area covered by a lookout point or points; may differentiate between seen areas, indirectly visible areas, and blind areas, or only between seen areas and blind areas. Also known as seen area map.

Basic weather conditions prescribed for flight under Visual Flight Rules: ceiling above 1,000 feet (300 m) and flight visibility in excess of 3 miles (5 km).

An NDVI-derived image of vegetation greenness compared to a very green reference such as a golf course.

Maximum distance at which a given object can just be seen by an observer with normal vision.

The inventory and planning actions taken to identify visual values and to establish objectives for managing those values; and the management actions taken to achieve the visual management objectives.

The visible physical features on a landscape (e.g., land, water, vegetation, animals, structures and other features).