Chandler Burning Fire Risk Index Explained
At Southampton Weather we have opted to use a standard known as the Chandler Burning Index.
The CBI is based on consecutive daily observations of temperatures,
relative humidity, wind speed and direction, and of course the last 24-hours rainfall.
The six standard components provide numeric ratings of relative potential for wildland fire.
The scale is basically one to a hundred so can also be used as a percentage of fire risk.
Rating and Colour
Fuels do not ignite readily from small firebrands although a more
heat source, such as lightning, may start fires in woods.
in open cured grasslands 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.
Fires can start from most accidental causes but, with the exception
lightning fires in some areas, the number of starts is generally
Fires in open cured grasslands will burn briskly and spread rapidly
windy days. Timber fires spread slowly to moderately fast. The
fire is of moderate intensity, although heavy concentrations
especially draped fuel, may burn hot. Short-distance spotting may
is not persistent. Fires are not likely to become serious and
All fine dead fuels ignite readily and fires start easily from most
Unattended brush and campfires are likely to escape. Fires
rapidly and short-distance spotting is common. High-intensity
may develop on slopes or in concentrations of fine fuels. Fires
become serious and their control difficult unless they are
successfully while small.
Very High (VH)
Fires start easily from all causes and, immediately after ignition,
rapidly and increase quickly in intensity. Spot fires are a
danger. Fires burning in light fuels may quickly develop high
characteristics such as long-distance spotting and fire whirlwinds
they burn into heavier fuels.
Fires start quickly, spread furiously, and burn intensely. All fires
potentially serious. Development into high intensity burning
usually be faster and occur from smaller fires than in the very high
danger class. Direct attack is rarely possible and may be
except immediately after ignition. Fires that develop headway in
slash or in conifer stands may be unmanageable while the
burning condition lasts. Under these conditions the only effective
safe control action is on the flanks until the weather changes or the