Interpreting Fire Danger

Fire Danger is a general indicator of all factors that affect flammability, fire spread, the physical impacts of fire, and the level of difficulty to control a fire. Fire Danger classes are derived from the Fire Weather Index. The following interpretations are based on observations of North American fires.

FIRE DANGER
CLASS	FIRE CHARACTERISTICS	FIRE SUPPRESSION DIFFICULTY
LOW	Creeping surface fires	No control problems unless fire is deep burning
MODERATE	Surface fires may spread vigorously or with moderate fire intensity*	Fire can be controlled by direct attack with hand tools and water
HIGH	Fast spreading or moderate to high intensity fire	Fire control requires power pumps and/or fire break construction using mechanized line-building tools
EXTREME	Fast spreading or high intensity fire	Very difficult to control. Indirect attack using drip torches from control lines may work

Additional information on the Canadian Fire Weather Index System

*Fire intensity is the rate of heat energy released at the front of the fire. Increasing flame lengths indicate increasing Fire Intensity. Suppression of peat fires are explained in the Drought Code Interpretation page.

See References