Technical glossary

Campaign Fire – A fire of such size, complexity and/or priority that its extinction requires a large organization, high resource commitment, significant expenditure, and prolonged suppression activity. Synonym - Project Fire.

Canadian Forest Fire Behaviour Prediction (FBP) System – A subsystem of the Canadian Forest Fire Danger Rating System. The FBP System provides quantitative outputs of selected fire behaviour characteristics for certain major Canadian fuel types and topographic situations. For example, head fire rate of spread, which can be adjusted for the mechanical effects of slope, is expressed in metres per minute (m/min). The system depends partly on the Canadian Forest Fire Weather Index System components as inputs.

Canadian Forest Fire Danger Rating System (CFFDRS) – The national system of rating fire danger in Canada; referred to as the Canadian Forest Fire Behaviour or Behaviour Rating System before 1976. The CFFDRS includes all guides to the evaluation of fire danger and the prediction of fire behaviour such as the Canadian Forest Fire weather Index System and Canadian Forest Fire Behaviour Prediction System.

Canadian Forest Fire Weather Index (FWI) System – A subsystem of the Canadian Forest Fire Danger Rating System; referred to previously by a variety of names (e.g. Canadian Forest Fire Weather Index, Canadian Fire Weather Index, Canadian Forest Fire Weather Index Tables). The components of the FWI System provide numerical ratings of relative fire potential in a standard fuel type (i.e. a mature pine stand) on level terrain, based solely on consecutive observations of four fire weather elements measured daily at noon (1200 hours local standard time or 1300 hours daylight saving time) at a suitable fire weather station; the elements are dry-bulb temperature, relative humidity, wind speed, and precipitation. The system provides a uniform method of rating fire danger across Canada.

The FWI System consists of six components. The first three are fuel moisture codes that follow daily changes in the moisture contents of three classes of forest fuel; higher values represent lower moisture contents and hence greater flammability. The final three components are fire behaviour indexes representing rate of spread, amount of available fuel, and fire intensity; their values increase as fire weather severity worsens.

The six standard codes and indexes of the FWI System are:

• Fine Fuel Moisture Code (FFMC) – A numerical rating of the moisture content of litter and other cured fine fuels. This code indicates the relative ease of ignition and flammability of fine fuel.
• Duff Moisture Code (DMC) – A numerical rating of the average moisture content of loosely compacted organic layers of moderate depth. This code indicates fuel consumption in moderate duff layers and medium-sized woody material.
• Drought Code (DC) – A numerical rating of the average moisture content of deep, compact, organic layers. This code indicates seasonal drought effects on forest fuels, and the amount of smouldering in deep duff layers and large logs.
• Initial Spread Index (ISI) – A numerical rating of the expected rate of fire spread. It combines the effects of wind and FFMC on rate of spread but excludes the influence of variable quantities of fuel.
• Buildup Index (BUI) – A numerical rating of the total amount of fuel available for combustion that combines DMC and DC. (Referred to as the Adjusted Duff Moisture Code or ADMC between 1969 and 1975).
• Fire weather Index (FWI) – A numerical rating of fire intensity that combines ISI and BUI. It is suitable as a general index of fire danger throughout the forested areas of Canada.

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Candle or Candling – See Torch or Torching under Fire Behaviour.

Centrifugal Pump – A pump that expels water by centrifugal force through the ports of a circular impeller rotating at high speed. This type of pump allows the discharge line to be shut off while the pump is running.

Chicot – See Snag.

Closed Area – An area in which specified activities or entry are temporarily restricted by agency legislation to reduce risk of man-caused fire. In some jurisdictions a closed area is called a restricted travel zone or a restricted fire zone.

Cold Trailing – Note Fire Suppression.

Combustion – A chemical oxidation-type process in which heat is produced (i.e. a substance is combined with oxygen). In the case of forest fires, living and dead fuels are converted to mainly carbon dioxide and water vapour, and heat energy is released very rapidly. Flaming combustion is characterized by the movement of a visible flame through the fuel bed. On the other hand, smouldering or glowing combustion is generally associated with the residual burning of forest fuels following flaming combustion.

Combustion actually consists of three more or less distinct but overlapping phases:

• Preheating Phase – Unburned fuel is raised to its ignition temperature and gaseous vapours begin to evolve.
• Distillation or Gaseous Phase – The flammable gases escaping from the fuel surface are ignited in the presence of oxygen. Energy in the form of heat and light is produced.
• Charcoal or Solid Phase – The presence of combustible vapours above the fuel is too low to support a persistent flame. The residual solid fuel or char burns away slowly.

Control a Fire – To complete a control line around a fire, any spot fires therefrom, and any interior island(s) to be saved; burning out any unburned areas adjacent to the fire side of the control lines; burning off any unwanted island(s) inside the control lines; and cooling down all hot spots that are immediate threats to the control line until the lines can be expected to hold under foreseeable conditions. Stages of Control are:

• Out of Control – Describes a wildfire not responding or only responding on a limited basis to suppression action such that perimeter spread is not being contained.
• Being Held – Indicates that with currently committed resources, sufficient suppression action has been taken that the fire is not likely to spread beyond existent or predetermined boundaries under prevailing and forecasted conditions.
• Being Observed – Currently not receiving suppression action, due to agency policy and management guidelines.
• Under Control – Having received sufficient suppression action to ensure no further spread of the fire.
• Being Patrolled – In a state of mop-up, being walked over and checked.
• Out – Having been extinguished.

Control Line – A comprehensive term for all constructed or natural fire barriers and treated fire perimeter used to control a fire. Note Fireguard and Fireline.

Convection Column – The definable plume of hot gases, smoke, firebrands, and other combustion by-products produced by and rising above a fire. Note Smoke Column under Smoke (2).

Cover Type – The designation of a vegetation complex according to its dominant species, age, and/or form.

Crown Scorch – Browning of the needles or leaves in the crown of a tree or shrub caused by the heat rising above a surface fire as a result of convection.