Flanking Fire

Flanking Fire Technique

The flanking-fire technique consists of treating an area with lines of fire set directly into the wind. The lines spread at right angles to the wind. This technique requires considerable knowledge of fire behavior, particularly if used by itself. It is used quite often to secure the flanks of a strip-heading fire or backing fire as it progresses. It is sometimes used to supplement a backing fire in areas of light fuel or under more humid weather conditions. It is useful on a small area or to facilitate burning a large area in a relatively short time when a line-heading fire would be too intense.

This method of firing can stand little variation in wind direction and requires expert crew coordination and timing. For safety, all lines of a flank fire should be ignited simultaneously and all torch people should keep abreast of one another. If only one or two torch people are available, this technique is usually altered to set the ignition lines 45 degrees into the wind.

In the hilly regions, any ignition line that drops perpendicularly off a ridge creates a flanking fire under no-wind conditions. If several lines are ignited off the end of a ridge or knoll, the pattern looks like a chevron or maple leaf.

Factors associated with flanking fires:

• Always secure downwind base line first.
• Fuel loading should be light to medium-less than 8 tons per acre.
• Wind direction must be steady.
• Best used in medium-to-large sawtimber.
• Allows fast area ignition.
• Needs few control lines.
• In areas with a high understory, multiple torch people are needed and coordination is very important.
• Use radio communications whenever torch people cannot see one another.
• Useful in securing flanks of other fire types (for example, strip-heading fire or backing fire).