Fire Danger Ratings

Fire Danger Rating and Color Code Blue Mountain Plan Adjective Class Used NWCG Recommended Adjective Class Description
Low (L) (Green)
Historically there have been few fires at this range of index values. Fuels do not ignite readily from small firebrands, although a more intense heat source, such as lightning, may start many fires in duff or punky wood. Fires in open cured grassland may burn freely a few hours after rain, but woods fires spread slowly by creeping or smoldering, and burn in irregular fingers. There is little danger of spotting.
Moderate (M) (Blue)
Historically fire have occurred during this range of index values but few large fires (as defined in the analysis) have occurred. Fires can start from most accidental causes, but with the exception of lightning fires in some areas, the number of starts is generally low. Fires in open-cured grassland will burn briskly and spread rapidly on windy days. Timber fires spread slowly to moderately fast. The average fire is of moderate intensity, although heavy concentrations of fuel, especially draped fuel, may burn hot.
High (H) (Yellow)
Historically large fire have occurred during this range of index values. There is less probability of high intensity, high resistance to control fires than in the Extreme category. Large fires during this range of index values are most related to fine fuels. All fine dead fuels ignite readily and fires start easily from most causes. Unattended brush and campfires are likely to escape. Fires spread rapidly and short-distance spotting is common. High-intensity burning may develop on slopes or in concentrations of fine fuel. Fire may become serious and their control difficult, unless they are attacked successfully while small.
Extreme (E) (Red)
Historically large fire have occurred at a higher rate than during the High range of index values. Large fires have a higher resistance to control due to greater intensity, more fuel (large and live fuels) participating in the fire due to all components of the fuel being more available to burn. Fires start quickly, spread furiously, and burn intensely. All fires are potentially serious. Development into high intensity burning will usually be faster and occur from smaller fires than in the very high danger class. Direct attack is rarely possible, and may be dangerous, except immediately after ignition. Fires that develop headway in heavy slash or in conifer stands may be unmanageable while the extreme burning condition lasts. Under these conditions, the only effective and safe control action is on the flanks until the weather changes or the fuel supply lessens.