Updated live — Source: CWFIS / Natural Resources Canada  | ← Canada Fire Central

The HFI estimates the energy output per unit length of fire front. It determines suppression difficulty and whether aerial attack is needed.

Color	Value	Category	Description
	0 – 500 kW/m	Low	Hand crews can suppress fire. No aerial attack needed.
	500 – 2000 kW/m	Moderate	Hand crews have difficulty. Aerial attack may assist.
	2000 – 4000 kW/m	High	Hand crews ineffective. Aerial attack required.
	4000 – 10000 kW/m	Very High	Aerial attack difficult. Extreme fire behavior.
	10000+ kW/m	Extreme	Fire beyond control. Evacuation priority.