Ministry of Forests, Lands and Natural Resource Operations - Wildfire Management Branch
The Fire Intensity Rank System enables firefighters to communicate a summarized assessment of fire behaviour.Rank 1
Smouldering ground or creeping surface fire.
This is a smouldering ground fire or a fire that burns in the ground fuel layer. These fires have no open flame and produce white smoke.
Firebrands and going fires tend to be virtually self-extinguishing unless high DC and/or BUI values prevail, in which case extensive mop-up is generally required.
Low vigour surface fire.
Rate of spread: less than 1.5m/min.
This is a surface fire or a fire that burns in the surface fuel layer, excluding the crowns of trees. These fires produce visible open flame; have little or no spread, which is the speed at which the fire extends; and have an unorganized flame front or a flame front that does not exhibit all the same characteristics.
Direct manual attack at fire's head or flanks by fire fighters with hand tools and water possible. Constructed fire guard should hold.
Moderately vigorous surface fire.
Rate of spread: 1.5 - 3.0 m/min.
This is a vigorous surface fire with a moderate rate of spread. They have an organized front and may display "candling", which is when a tree's fuels ignite and flare up, along the perimeter and/or within the fire.
Hand-constructed fire guards likely to be challenged. Heavy equipment (bulldozers, pumpers, retardant aircraft, skimmers, helicopter w/bucket) generally successful in controlling fire.
Highly vigorous surface fire, torching (or passive crown fire).
Rate of spread: 3.0 - 6.0 m/min.
This type of fire produces grey to black smoke, has an organized surface flame front, and has a moderate to fast rate of spread along the ground. Short aerial bursts and short range spotting will occur with these fires.
Control efforts at fire's head may fail.
Extremely vigourous surface fire or active crown fire.
Rate of spread: 6.0 - 18.0 m/min.)
This type of fire produces black to copper smoke, has an organized crown fire front, moderate to long-range spotting and independent spot fire growth.
Very difficult to control. Suppression action must be restricted to fire's flanks. Indirect attack with aerial ignition (i.e., helitorch and/or aid dispenser) may be effective.
Blow-up or conflagration, extreme fire behaviour.
Rate of spread in excess of 18.0 m/min.
Violent fire behaviour occurs with this type of fire. An organized crown fire front, moderate to long-range spotting and independent spot fire growth are characteristic of this fire type. There may be the presence of fireballs and whirls.
Violent physical behaviour probable. Suppression actions should not be attempted until burning conditions ameliorate.