The BC Wildfire Service uses a ranking scale from 1 to 6 to describe fire behaviour based on a set of visual indicators.
​
The following page describes fire behaviour "ranks" and examples of firefighting tactics that may be used to address that type of fire behaviour:
Rank 1 – Smouldering ground fire
Rank 2 – Low vigour surface fire
Rank 3 – Moderately vigorous surface fire
Rank 4 – Highly vigorous surface fire with torching, or passive crown fire
Rank 5 – Extremely vigorous surface fire or active crown fire
The limited options available include indirect attack and planned ignitions to remove fuel in the path of this type of fire behaviour. Ground operations are often restricted to fighting the least active sections of the fire or conducting ground ignition operations from secure control lines with readily available escape routes and safety zones.
Rank 6 – A blow up or conflagration; extreme and aggressive fire behaviour
Firefighting under these conditions is extremely dangerous. Suppression efforts will be well away from active fire behaviour and may include preparing structure protection measures or conducting indirect large-scale ignition operations in an attempt to steer the fire. Often, the safest and most prudent strategy is to pull resources back to safe areas, ensure that personnel and the general public are safe, and wait for fire behaviour to lessen before re-engaging in fire suppression operations.