NWCG Glossary of Wildland Fire, PMS 205

A type of bleeder valve designed for installation at convenient points in hose lines to permit drawing off water for filling backpack pumps or other use without interfering with pump or nozzle operation.

Any body of water including lakes, rivers, streams and ponds whether or not they contain aquatic life.

A disturbance that transfers energy from one point to another point and may take the form of a deformation of pressure or temperature. In the atmosphere such disturbances may result in major storms or merely result in changes in cloud, wind and temperature conditions. Development of a wave on a front usually slows the advance of the front due to transfer of energy to the wave development and movement. 

In aviation forecasting, an expression of hazardous weather conditions not predicted in the zone weather forecast, as they affect the operation of air traffic.

A field collected in the ICS 209 containing a brief summary of how the current weather is affecting the incident and how the anticipated weather will affect the incident.

Part of the National Fire Danger Rating System (NFDRS).  Number used to determine seasonal risk class for a protection unit, calculated by multiplying peak monthly average by two and adding seasonal monthly average.

The contractor furnishes all equipment operating supplies.

A low expansion foam type with few and varied bubbles and rapid drain time which is used for rapid penetration and fire extinguishment.

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.

Fire retardants mixed with water and stored in tanks at air attack bases for immediate use by airtankers.

Water with added chemicals, called wetting agents, that increase water's spreading and penetrating properties due to a reduction in surface tension.

The difference between the wet and dry-bulb temperatures recorded by a psychrometer; used in conjunction with the dry-bulb temperature as a measure of the relative humidity of the air.

The lowest temperature to which air can be cooled by evaporating water into it at a constant pressure when the heat required for evaporation is supplied by the cooling of the air. It is measured by the wet bulb thermometer, which usually employs wetted wicking on the bulb as a cooling (through evaporation) device.

In a psychrometer, the thermometer with its bulb covered with a jacket of clean muslin which is saturated with distilled water before an observation.

A chemical that when added to water reduces the surface tension of the solution and causes it to spread and penetrate exposed objects more effectively than the untreated water.

A widespread rain that over an extended period of time significantly reduces fire danger. One-tenth of an inch may be sufficient to reduce fire danger in grass fuel models. One half inch may be necessary for timber fuels under closed canopies.

The distance from the centerline of the front axle to the centerline of the rear axle. For a tandem rear axle vehicle the center line is midpoint between the centers of the two rear axles.

A loose limb, top, or piece of bark lodged in a tree, which may fall on anyone working beneath it.

A wildland fire originating from an unplanned ignition, such as lightning, volcanos, unauthorized and accidental human caused fires, and prescribed fires that are declared wildfires.

An event dealing with a wildland fire originating from an unplanned ignition, such as lightning, volcanos, unauthorized and accidental human caused fires, and prescribed fires that are declared wildfires.

Identifying something that started a wildfire.

The range of options available for response to a wildfire.

An appropriate management response to wildfire or prescribed fire that results in curtailment of fire spread and eliminates all identified threats from the particular fire.

An area in which development is essentially non-existent, except for roads, railroads, powerlines, and similar transportation facilities. Structures, if any, are widely scattered.

Any non-structure fire that occurs in vegetation or natural fuels. Includes wildfires and prescribed fires.

An internet-based information system, providing national views of weather and fire potential, including national fire danger and weather maps and satellite-derived greenness maps.

Eleven principles describing tangible behaviors that reflect and demonstrate the wildland fire leadership values.

Three guiding values that should be the basis for the decisions that leaders make.

A group of 7-10 highly skilled personnel specifically associated with the planning and implementation of planned and unplanned wildland fire and hazardous fuels treatments. May be classified as a Type 1 or Type 2 dependent on qualifications and experience.

Any accident where one or more fatalities occur and/or three or more personnel are inpatient hospitalized as a direct result, or in support of wildland fire suppression or prescribed fire operations. Accident may result in substantial property or equipment damage of $250,000 or more. 

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

The line, area, or zone where structures and other human development meet or intermingle with undeveloped wildland or vegetation fuels.​​

A flag that indicates if the presence of Wildland Urban Interface (WUI) increased the cost or management complexity of a wildfire.

The horizontal movement of air relative to the surface of the earth.

Compass direction from which wind is blowing.

A chart of wind speed in relation to height, most commonly determined by a pilot balloon observation.

A variation in wind speed and/or direction in a layer of the atmosphere or between layers. The variation may be in the horizontal or vertical dimensions and may result in significant turbulence depending upon the magnitude of the wind speed/direction differences. A strong wind shear may act like an inversion and inhibit plume rise. It may also fracture the smoke plume, not allowing smoke to rise much above terrain levels. A strong horizontal anticyclonic shear results in downward motion and may bring smoke aloft to the surface.

For aviation purposes, a change in the average wind direction of 45 degrees or more which takes place in less than 15 minutes if the wind speed during this period is 6 knots (3 m/s) or greater.

For ground observation purposes, a change of at least 45 degrees in the direction of a significant wind, which occurs in a relatively short time frame.

Wind, in miles per hour, measured at 20 feet above open, level ground or as adjusted to meet this standard to compensate for height of ground cover, uneven ground, and nearby obstructions.

Wind, in miles per hour, measured at 20 feet above ground, or above the average height of vegetation, and averaged over at least a 10-minute period.

Wind directions used to calculate fire behavior.

A char pattern that is created by the passage of wind around the trunk of a tree or pole-like object that creates vortices on the lee side and an area of stability.  The area of stability allows the heat and char pattern to rise higher on the lee side of the object.  Generally, the stronger the wind, the higher the wind vortex flame wrap will be.  White this is not a fire pattern indicator, it is a general indication of the direction of the wind at the time the pattern was created.

A wildland fire that is controlled by a strong consistent wind.

Tree that has been uprooted or broken off by wind.

Burning slash that has been piled into long continuous rows. Also includes wildfire in vegetation planted to protect improvements or agriculture.