Compiled by Marcy Stamper
This glossary includes standard terminology as well as colloquial terms that often appear in updates on fire status.
Parts of a fire
fingers of a fire: long, narrow extensions projecting from the main body
flank of a fire: the part of the perimeter roughly parallel to the main direction of spread
head of a fire: the side of the fire with the fastest rate of spread; also called leading edge
island: an area of unburned fuel within the perimeter
perimeter: the entire outer edge of a fire
point of origin: the precise location where the fire first ignited
rear of a fire: the slowest-spreading portion of a fire, generally heading into the wind or downslope; also called heel
spot fire: fire ignited outside the perimeter
Fire behavior
backing fire: the slower-moving part of the fire, generally moving into the wind or downslope
blow-up: an acceleration or intensification significant enough to change fire-control plans; compare flare-up
convection column: rising column of gases, smoke and other debris produced by a fire
creeping: fire burning with a low flame and spreading slowly; also called skunking
crown fire: a fire that moves from the top of one tree or shrub to another; which can move independently of the fire activity on the ground
dirty burn: an area where there is still a lot of standing, half-burned fuel susceptible to reburning
flare-up: a brief acceleration or intensification of fire that does not change fire-control plans; compare blow-up
hot spot: a particularly active part of a fire
plume-dominated fire: fire with behavior dominated by the convection column that can spread in any direction because the fire will pull burning debris into the column and spit it out anywhere
running: fire that is spreading rapidly with a well-defined head
skunking: fire burning with a low flame and spreading slowly; also called creeping
sleeper fire: fire started by lightning strikes that go underground and erupt several days or weeks later from wind or hot, dry conditions; also called holdover fire
a smoke: evidence of a new fire, often after a lightning strike (colloquial)
smoldering: fire burning without flame and barely spreading
spotting: starting new fires outside the perimeter by sparks or embers carried by the wind
torching: burning of foliage of a tree or small group of trees from the bottom up; depending on the number of trees involved, may be described as single or group torching
Control and suppression
anchor point: a barrier from which to start building a fire line
burnout: a tactic that involves burning the area between an established control line some distance from the fire and the main fire; sometimes called backburn or backfire, but the official term is burnout
containment: a control line completed around the fire and associated spot fires that can be expected to stop the fire from spreading
control line: an inclusive term for all constructed or natural barriers used to contain a fire
control: completion of a control line around the perimeter, spot fires and interior islands; burnout of unburned areas adjacent to the control lines; cooling of all hot spots
coyote tactics: use of spike camps; also called coyoting
direct attack: establishing a control line on the perimeter of the fire by digging down to mineral soil
fire line: a control line scraped or dug to mineral soil; there are hand lines (dug with shovels) and dozer lines (dug by bulldozers)
firing operations: setting prescribed fire or burnouts using drip torches or aerial ignition
hot shots: highly trained fire crews used mainly to build fire line by hand, often in rugged terrain
indirect attack: establishing a control line some distance from the main fire, either by digging a line or using a natural barrier such as a road or river
management action points: geographic points on the ground or specific points in time that guide fire management; also called trigger points
mop-up: extinguishing or removing burning material near control lines and felling snags to make an area safe after it has burned
patrol status: going back and forth over a control line to suppress spot fires and extinguish hot spots
point protection: specific structures or communities identified for protection
spike camp: where firefighters stay to work on a fire when it is far from roads or involves a long hike; a line spike camp refers to a camp on the fire line
Fuels
jack-strawed trees: trees scattered like toothpicks, generally from a windstorm
ladder fuels: surface fuels such as needles or leaves, and shrubs and lower branches that provide a path for the fire to move from the ground to the tree canopy
light, flashy fuels: dry grasses and shrubs
Weather
Haines index: measures the stability and dryness of the air over the fire to indicate the potential for wildfire growth; the index ranges from 2 to 6—the drier and more unstable the lower atmosphere is, the higher the number
Other terms
defensible space: an area around a house cleared of flammable vegetation and other potential ignition sources and kept well-maintained and watered
Sources: National Wildfire Coordinating Group Glossary of Wildland Fire Terminology, a glossary on WildlandFire.com, and interviews with public information officers from the incident management teams and local firefighters.
