These graphs present Forest Fire Danger Index and Grass Fire Danger Index against weather conditions for the last 31 days.
The graphs are updated every day just after 09:00 hours.

The data displayed represents a FORECAST of the FFDI/GFDI Indices for later the same day
The highest risk period being between ( 14:00 to 16:00 ) hours.

The Forest Fire Danger Index (FFDI) is a numeric rating between 0 and 100(+), The new scale and the associated conditions described below are based on the Forest Fire Danger Index (FFDI) and the Grassland Fire Danger Index (GFDI). The FFDI is the basis for determining the FDR and provides an assessment of the potential fire behaviour, the difficulty of suppressing a fire, and the potential impact on the community should a bushfire occur on a given day. The FFDI was developed in the 1960s by CSIRO scientist A.G. McArthur to measure the degree of danger of fire in Australian forests. The index combines a record of dryness, based on rainfall and evaporation, with meteorological variables for wind speed, temperature and humidity. The GFDI is based on the FFDI approach and incorporates the degree of grassland curing (drying).

A rating of: FFDI

• 0 - 11 suggests Low Moderate probability of fire ignitions
• 12 - 24 suggests High probability of fire ignitions
• 25 - 49 suggests Very High probability of fire ignitions
• 50 - 74 suggests Severe fire behavior
• 75 - 99 suggests Extreme fire behavior
• 100+ suggests Code Red / Catastrophic fire behavior

• 0 - 11 suggests Low Moderate probability of fire ignitions
• 12 - 24 suggests High probability of fire ignitions
• 25 - 49 suggests Very High probability of fire ignitions
• 50 - 74 suggests Severe fire behavior
• 75 - 99 suggests Extreme fire behavior
• 100+ suggests Code Red / Catastrophic fire behavior

The Fine Fuel Moisture Code (FFMC) is a numeric rating between 0 and 101 of the moisture content of litter and other cured fine fuels. This code is an indicator of the relative ease of ignition and the flammability of fine fuel. It is calculated using wind, temperature, relative humidity and rain.

A rating of:

• under 58 suggests low probability of fire ignitions
• 58 - 74 suggests 50% of fires will ignite
• 74 to 86 suggests all fires will rapidly ignite
• over 86 suggests extreme fire behavior

The Duff Moisture Code (DMC) is a numeric rating between 0 and 150 of the average moisture content of loosely compacted organic layers of moderate depth. This code gives an indication of fuel consumption in moderate duff layers and medium-size woody material. It uses temperature, relative humidity and rain in it's calculation.

A rating of

• greater than 30 is high fire risk
• greater than 40 is extreme fire risk

THE BYRAM-KEETCH DROUGHT INDEX (BKDI) and DROUGHT FACTOR (DF) The Byram-Keetch Drought Index (BKDI) attempts to measure the amount of precipitation necessary to return the soil to full field capacity. It is a closed system ranging from 0 to 203 units (0 - 800 imperial) and represents a moisture regime from 0 to 203 millimetres (0 - 8 inches) of water through the soil layer. At 203 millimetres (8in) of water, the KBDI assumes saturation. Zero is the point of no moisture deficiency and 203 (800) is the maximum drought that is possible. At any point along the scale, the index number indicates the amount of net rainfall that is required to reduce the index to zero, or saturation. The inputs for KBDI are weather station latitude, mean annual precipitation, maximum dry bulb temperature, and the last 24 hours of rainfall. Reduction in drought occurs only when rainfall exceeds 5mm (0.20 inch) (called net rainfall).

Drought Factor (DF): A key component of the FFDI is the modelling of the dryness of the fuel. This is expressed by the Drought Factor (DF), which ranges from 0 to 10. If this is multiplied by 10 and called a percent, it gives the percentage of fine fuel that would be removed by a fire under the current conditions. The DF is based on recent rainfall and on the Byram-Keetch Drought Index (BKDI).

The Drought Code (DC) is a numeric rating between 0 and 800 of the average moisture content of deep, compact organic layers. This code is a useful indicator of seasonal drought effects on forest fuels and the amount of smoldering in deep duff layers and large logs.

A drought code of:

• 200 is a high risk of fire
• 300 is a very high risk of fire
• 350 is an extreme risk of fire

The Initial Spread Index (ISI) is a numeric rating between 0 and 100 of the expected rate of fire spread. It combines the effects of wind and the FFMC on rate of spread without the influence of variable quantities of fuel. It uses the FFMC rating and Wind in it's calculation.

An ISI of greater than 10 will see rapid spread of fires.

The Buildup Index (BUI) is a numeric rating between 0 and 200 of the total amount of fuel available for combustion. To calculate it combines the DMC and the DC..

A BUI of greater than 40 is a high fire risk with a BUI of greater than 60 is an extreme fire risk.

The Fire Weather Index (FWI) is a numeric rating between 0 and 150 of fire intensity. It combines the Initial Spread Index and the Buildup Index. It is suitable as a general index of fire danger.

The ratings are based on the following FWI scores:

• FWI score of less than 7.0 is a low risk of fire
• FWI score of between 7.0 and 15.9 is a moderate risk of fire
• FWI score of between 16 and 24.9 is a high risk of fire
• FWI score of between 25 and 30.9 is a very high risk of fire
• FWI score of 31 or more is an extreme risk of fire