FOX31 Denver’s glossary of wildfire terms and slang

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DENVER — How safe is your house behind a scratch line? What does it mean when officials say a fire is “contained?” With Colorado’s wildfire season very much under way, FOX31 Denver and CNN have assembled a glossary of the common phrases used by fire officials and firefighters.

  • Backfire: A fire set along the inner edge of a fire line to consume the fuel in the path of a wildfire and/or change the direction of force of the fire’s convection column.
  • Bambi bucket: A collapsible bucket slung below a helicopter. Used to dip water from a variety of sources for fire suppression.
  • Blow-up: A sudden increase in fire intensity, or rate of spread strong enough to prevent direct control or to upset control plans. Blow-ups are often accompanied by violent convection and may have other characteristics of a fire storm. (See Flare-up.)
  • Burn out: Setting fire inside a control line to widen it or consume fuel between the edge of the fire and the control line.
  • Complex: Two or more incidents located in the same general area, assigned to a single incident commander or unified command.
  • Contain a fire: A fuel break around the fire has been completed. This break may include natural barriers or a manually and/or mechanically constructed line.
  • Control a fire: The complete extinguishing of a fire, including spot fires. The fire line has been strengthened so flare-ups from within the perimeter of the fire won’t break through this line.
  • Control line: All built or natural fire barriers and treated fire edge used to control a fire.
  • Crown fire (crowning): The movement of fire through the crowns of trees or shrubs, more or less independently of the surface fire.
  • Direct attack: Any treatment of burning fuel, such as by wetting, smothering or chemically quenching the fire or by physically separating burning from unburned fuel.
  • Dozer: Any tracked vehicle with a front-mounted blade used for exposing mineral soil.
  • Dozer line: A fire line constructed by the front blade of a dozer.
  • Extreme fire behavior: “Extreme” implies a level of fire behavior characteristics that ordinarily precludes methods of direct control action. One of more of the following is usually involved: high rate of spread, prolific crowning and/or spotting, presence of fire whirls, strong convection column. Predictability is difficult because such fires often exercise some degree of influence on their environment and behave erratically, sometimes dangerously.
  • Fire behavior: The manner in which a fire reacts to the influences of fuel, weather and topography.
  • Fire behavior forecast: Prediction of probable fire behavior, usually prepared by a fire behavior officer in support of fire suppression or prescribed burning operations.
  • Fire behavior specialist: A person responsible to the planning section chief for establishing a weather data collection system and for developing fire behavior predictions based on fire history, fuel, weather and topography.
  • Fire front: The part of a fire within which continuous flaming combustion is taking place. Unless otherwise specified the fire front is assumed to be the leading edge of the fire perimeter. In ground fires, the fire front may be mainly smoldering combustion.
  • Fire line: A linear fire barrier that is scraped or dug to mineral soil.
  • Flare-up: Any sudden acceleration of fire spread or intensification of a fire. Unlike a blow-up, a flare-up lasts a relatively short time and does not radically change control plans.
  • Hand line: A fire line built with hand tools.
  • Hotshot crew: A highly trained fire crew used mainly to build fire lines by hand.
  • Hotspot: A particularly active part of a fire.
  • Hotspotting: Reducing or stopping the spread of fire at points of particularly rapid rate of spread or special threat, generally the first step in prompt control, with emphasis on first priorities.
  • Mop-up: To make a fire safe or reduce residual smoke after the fire has been controlled — by extinguishing or removing burning material along or near the control line, felling snags or moving logs so they won’t roll downhill.
  • Prescribed fire: Any fire ignited by management actions under certain, predetermined conditions to meet specific objectives related to hazardous fuels or habitat improvement. A written, approved prescribed fire plan must exist, and NEPA requirements (National Environmental Policy Act) must be met, prior to ignition.
  • Run (of a fire): The rapid advance of the head of a fire with a marked change in fire line intensity and rate of spread from that noted before and after the advance.
  • Safety zone: An area cleared of flammable materials used for escape in the event the line is outflanked or in case a spot fire causes fuels outside the control line to render the line unsafe. In firing operations, crews progress so as to maintain a safety zone close at hand allowing the fuels inside the control line to be consumed before going ahead. Safety zones may also be constructed as integral parts of fuel breaks; they are greatly enlarged areas which can be used with relative safety by firefighters and their equipment in the event of a blowup in the vicinity.
  • Scratch line: An unfinished preliminary fire line hastily established or built as an emergency measure to check the spread of fire.
  • Slop-over: A fire edge that crosses a control line or natural barrier intended to contain the fire.
  • Spot fire: A fire ignited outside the perimeter of the main fire by flying sparks or embers.
  • Torching: The ignition and flare-up of a tree or small group of trees, usually from bottom to top.
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