|Class Ignition Potential||Interpretation|
|Low||Low fire intensity. Fire will spread slowly or be self-extinguishing. Grassland fires can be successfully controlled using hand tools.|
|Medium||Moderate fire intensity in grass. Hand tools will be effective along the fire�s flanks, but water under pressure (pumps, hose) may be required to suppress the head fire in grasslands.|
|High||High fire intensity in grass. Direct attack at the fire�s head will require water under pressure, and mechanized equipment may be required to build control lines. (e.g: bulldozer)|
|Extreme||Very high fire intensity in grass. Fire control will require construction of control lines by mechanized equipment and water under pressure. Indirect attack by back-burning between control lines and the fire may be required.|
The FWI values refer to the fire intensity and general fire danger across the landscape, after taking into account of Initial Spread Index and Build Up Index. This index is related to the difficulty of fire control based on the head fire intensity and fire-fighting capability.
Image courtesy of the Malaysian Meteorological Department.