Technical glossary

Ignition Pattern – The manner in which a prescribed burn, backfire, or burnout, is set, determined by weather, fuel, ignition system, topographic and other factors having an influence on fire behaviour and the objective of the burn. Several methods are commonly used:

• Angled Strip Ignition – The setting of a number of lines of fire on an area at an angle to the wind. The effect is to create lines of fire with attributes of both a head fire and a flank fire. Somewhat similar to maple leaf ignition, except that the angled strip method is normally used on flat or uniform terrain whereas the maple leaf method is intended for hilly areas.
• Area Grid Ignition – The setting of a number of individual fires throughout an area so spaced that they will spread independently over most of the area before finally reinforcing one another. (In Ontario referred to as spot ignition).
• Backfire Ignition – The setting of a line of fire so that it will burn away from a control line against the wind or downhill. (In Ontario referred to as a single strip backfire).
• Centre Fire Ignition (Centre Firing) – The setting of fires in the centre of an area or concentrated to create a central convection column with additional fires set progressively and less concentrated near the outer control lines. As indrafts develop they draw the fire toward the centre. Synonym - Convection Burning.
• Flank Fire Ignition – The setting of a line of fire along a line parallel to the wind with the fire spreading at right angles to the wind or across a slope. (In Ontario referred to as a single strip flank fire).
• Head Fire Ignition – The setting of a line of fire so that it will burn with the wind or upslope away from a control line. (In Ontario referred to as a single strip head fire).
• Perimeter Fire Ignition (Perimeter Firing) – The setting of a series of fires or a line of fire around the perimeter of an area and allowing the fire(s) to burn toward the centre of the area. May or may not involve centre firing. Typically, fires are set first on the downwind side to produce a backfire, then along the sides of the area to produce flank fires, and then on the upwind side to produce a head fire.
• Strip Fire Ignition – The setting of successive parallel strips of fire (progressing outward toward the perimeter of the area), each one burning adjacent to the strip previously burned. May be used for backfires, flank fires, or head fires. (In Ontario referred to as multiple strip backfire, multiple strip flank fire, or multiple strip head fire).

Ignition Temperature – The minimum temperature at which ignition can take place and sustained combustion can occur. Synonym - Kindling Point.

Infrared Scanner – An optical-electronic system for identifying or obtaining imagery of thermal infrared radiation to detect non-smoking fires or fire perimeters through smoke. May also be used for fire mapping. The system may be operated from an aircraft, or hand-held on the ground. Note Thermal Imagery.

Initial Action – The steps taken after the report of a fire and before actual fire fighting begins on it. Note Initial Attack.

Initial Attack – The action taken to halt the spread or potential spread of a fire by the first fire fighting force to arrive at the fire. Note Initial Action.

Initial Attack Crew – Personnel trained, equipped and deployed to conduct suppression action to halt the spread or potential spread of a wildfire within the first burning period. Note Helitack Crew, Rappel Crew, and Suppression Crew.

Inspection Run – A pass over the target by the birddog aircraft or the airtanker to assess the flight path and target. Note Dummy Run and Lead-in.