The
following are descriptions of the five fire danger ratings.
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LOW
Fires are not easily started. Fuels do not ignite
readily from small firebrands, although, a more intense ignition
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
fires burning in forested areas spread slowly by creeping or smoldering
and burn in irregular fingers. There is also a danger of spotting. |
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MODERATE
Fires start easily and spread at a moderate rate. 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. Woods fires spread slowly to moderately
fast. The average fire is of moderate intensity, although heavy
concentrations of fuel may burn hot. Short-distance spotting
may occur, but is not persistent. Fires are not likely to become
serious, and control is relatively easy.
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HIGH
Fires start easily and spread at a fast rate. All fine dead fuels
ignite readily and fires start easily from most causes. Unattended
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 difficult to control unless they are hit hard and fast
while small.
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VERY
HIGH
Fires start very easily and spread at a very fast rate. Fires start
easily from all causes, spread rapidly and intensify quickly. Spot
fires are a constant danger. Fires burning in heavy fuels may quickly
develop high-intensity characteristics, such as long-distance spotting
and fire whirlwinds. Direct attack at the head of such fires is rarely
possible after they have been burning more than a few minutes.
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EXTREME
The fire situation is explosive and can result in extensive
property damage. Fires under extreme conditions 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 burning 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.
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