Southwest Florida Fire Index, Drought, Lee County >> Fire Graphs

Weather Station Fire Graphs - Southwest Florida

Graphs update once per day just before midnight. Graphs last updated on Monday May 20, 2013 - 11:57 pm

Chandler Burning Index - (CBI)

The Chandler Burning Index (CBI) uses the air temperature and relative humidity to calculate a numerical index of fire danger. That number is then equated to the Fire Danger severity of either extreme, very high, high, moderate, or low. It's based solely on weather conditions, with no adjustment for fuel moisture.

Fire Weather Index - (FWI)

To interpret the system, the three fuel moisture codes and the three behaviour indices need to be understood. Each code and index is a numerical rating related to likely fire behaviour. The scales start at zero, and except for the Fine Fuel Moisture Code which has a maximum of 99, all are open-ended. Low ratings indicate high moisture content, and ratings rise as moisture content decreases. Ratings rise as fire weather becomes more severe.

Drought Code - (DC)

The DC is a numerical rating of the moisture content of deep, compact, organic layers. It is a useful indicator of seasonal drought and shows the likelihood of fire involving the deep duff layers and large logs. A long period of dry weather (the system uses 52 days) is needed to dry out these fuels and affect the Drought Code. A DC rating of 200 is high, and 300 or more is extreme indicating that fire will involve deep sub-surface and heavy fuels. Burning off should not be permitted when the DC rating is above 300.

Duff Moisture Code - (DMC)

DMC is a numerical rating of the average moisture content of loosely compacted organic layers of moderate depth. The code indicates the depth that fire will burn in moderate duff layers and medium size woody material. Duff layers take longer than surface fuels to dry out but weather conditions over the past couple of weeks will significantly affect the DMC. The system applies a time lag of 12 days to calculate the DMC. A DMC rating of more than 30 is dry, and above 40 indicates that intensive burning will occur in the duff and medium fuels.

Build Up Index - (BUI)

This index shows the amount of fuel available for combustion, indicating how the fire will develop after initial spread. It is calculated from the Duff Moisture Code and the Drought Code.

The BUI scale starts at zero and is open-ended. A rating above 34 is high, above 77 is extreme.

Initial Spread Index - (ISI)

This indicates the rate fire will spread in its early stages. It is calculated from the FFMC rating and the wind factor.

The open-ended ISI scale starts at zero and a rating of 10 indicates high rate of spread shortly after ignition. A rating of 19 or more indicates extremely rapid rate of spread.

Fine Fuel Moisture Code - (FFMC)

This is a numerical rating of the moisture content of surface litter and other cured fine fuels. It shows the relative ease of ignition and flammability of fine fuels. The moisture content of fine fuels is very sensitive to the weather. Even a day of rain, or of fine and windy weather, will significantly affect the FFMC rating. The system uses a time lag of two-thirds of a day to accurately measure the moisture content in fine fuels. The FFMC rating is on a scale of 0 to 99. Any figure above 70 is high, and above 90 is extreme.

Temperature

Capeweather.com uses the highest temperature of the day recorded by our weather station. All data is processed just prior to midnight in an effort to have the largest sampling of data possible for the day prior to final data point selection and calculations.

Humidity

Capeweather.com uses the lowest humidity of the day as recoded by our weather station. All data is processed just prior to midnight in an effort to have the largest sampling of data possible for the day prior to final data point selection and calculations.

Windspeed

Capeweather.com uses the average wind speed for the entire day in our calculations. The calculation for the average is based upon the Total Wind Run (distance of wind travel throughout the day) then simply divided by the number of hours in the day! All data is processed just prior to midnight in an effort to have the largest sampling of data possible, prior to final data point selection and calculations.

Rainfall

Total Rainfall mesurement for the previous 24 hours are utilized in several of the above calculations, for this reason all data is processed just prior to midnight in an effort to have the largest sampling of data possible for the day prior to final calculations.

My Fire Weather Page The following is FWI Data for the Capeweather.com weather station.

Last Updated: 5/20/2013 11:45:55 PM

Date	Temp ºF	Humidity %	Wind Spd mph	Rainfall in	FFMC	DMC	DC	ISI	BUI	FWI	FFDC	SFDC	GFDC	CBI
5/20/2013	91.3	46	3	0.01	90.2	66	469	5.6	97	20.8	VH	EX	HI	27.2
5/19/2013	89.9	57	3	0.00	89.9	62	461	5.3	93	19.5	HI	EX	HI	14.0
5/18/2013	88.4	51	3	0.00	90.8	59	453	6.1	89	21.1	VH	EX	HI	20.1
5/17/2013	87.4	45	3	0.00	91.8	56	445	7.0	85	22.7	VH	EX	HI	28.2
5/16/2013	89.2	35	3	0.00	92.7	52	437	8.0	81	24.3	EX	EX	HI	48.5
5/15/2013	88.2	39	5	0.00	92.6	48	429	9.2	75	25.8	EX	EX	VH	39.2
5/14/2013	87.9	30	5	0.00	92.5	44	421	9.1	69	24.6	EX	EX	VH	62.2
5/13/2013	86.6	58	5	0.00	87.6	39	413	4.5	63	13.9	HI	EX	HI	12.8
5/12/2013	85.6	72	4	0.00	86.7	36	405	3.7	59	11.4	MD	EX	HI	4.3
5/11/2013	86.4	71	4	0.00	87.2	34	397	3.9	56	11.6	MD	EX	HI	4.7
5/10/2013	87.8	58	3	0.00	89.9	32	389	5.3	53	14.3	HI	EX	HI	12.9
5/9/2013	87.6	28	3	0.00	92.9	29	381	8.2	48	18.9	HI	EX	VH	68.6

Fire weather graphs and tabular data created using FWI Calculator Software