Fire Index - Richards Bay

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FWI Help Guide - Operational Interpretation

L = low fire danger M = moderate fire danger H = high fire danger VH = very high fire danger E = extreme fire danger

Codes/Indices	Values	Triggers
Fine Fuel Moisture Code Time Lag = 16 Hours	0~ 101	Í 58 Þ = 74 Þ ³ 86 Þ ³ 92 Þ	No fire ignitions 50% fire ignitions All fires will readily ignite Extreme fire behaviour
Duff Moisture Code Time Lag = 12 DAYS	0 ~150	> 30 Þ > 40 Þ	H VH SUSPEND the issue of fire permits
Drought Code Time Lag = 52 DAYS	0 ~ 800	³ 200 Þ ³ 300 Þ ³ 350 Þ	H VH SUSPEND the issue of fire permits Prolonged Mop Up following fires
Initial Spread Index	0 ~100	> 10 Þ	Rapid Spread of fires
BuildUp Index	0 ~200	> 40 Þ > 60 Þ	H VH SUSPEND the issue of fire permits
Fire Weather Index	0 ~150	³ 30 Þ	Extreme Fire Intensity / Control Difficulty

The moisture codes (FFMC, DMC and DC) indicate what fuels will be involved and their ease of ignition. This will vary during the season. Each code must be considered to assess potential burning characteristics.

Example: 1
FFMC = 86 DMC = 25 DC = 120

These ratings indicate:

fine fuels will ignite easily
fire will involve the light fuels and to a limited extent the medium and duff layer fuels
fire will not become deep seated

Example: 2
FFMC = 94 DMC = 45 DC = 320

These ratings indicate:

fine fuels will ignite extremely easily
fire will involve all fuel levels
extreme fire behaviour is likely
2. The fire behaviour indices (ISI, BUI, FWI) indicate the likely initial spread, total fuel availability, and potential intensity.

Example: 3
ISI = 5 BUI = 120 FWI = 21

These ratings indicate:

slow initial spread
high volume of fuel available for combutstion
potentially high level of fire intensity
In general terms, a hot, but slow moving fire. The type of fire likely to occur on a windless day in mid-summer after a long dry period.

Example: 4
ISI = 25 BUI = 10 FWI = 21
Note the same FWI as example 3.

These ratings indicate:

extremely fast initial spread
low volume of fuel available for combustion
potentially high level of intensity
In general, a fast moving fire involving fine fuels only.

Likely to be either:

a fire in early spring of late autumn when medium and heavy fuels have a moisture content
and winds are strong, or
a fire after rain on a day with strong winds

Explanation taken from http://nrfa.fire.org.nz/fire_weather/fwi_help/values_triggers.htm

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