Fire Weather Maps: Day One | Day Two Text Outlooks: Day One | Day Two Specialty Fire Weather / Drought Graphics: Afternoon Temperature Forecast | Afternoon RH% Forecast | Chandler Burning Index Forecast | Precipitation Frequency Forecast *Description of Specialty Products Below

Description of Monthly Fire Potential and the Chandler Burning Index

The monthly fire weather forecast characterizes the weather-induced fire potential for the continental United States as an average for the month. The color maps depict percentiles that are similar to those derived in the National Fire-Danger Rating System. Higher percentiles indicate higher than normal fire potential. The monthly fire potential is represented by a modified version of the Chandler Burning Index (CBI). CBI provides a measure of the effects of average monthly temperature and humidity on fire intensity and rate of spread (not the same as NFDRS rate of spread. Both the intensity and spread components of the Index are linearly related to temperature (an increase in temperature results in a proportionately higher Index), but are exponentially related to humidity (a small decrease in humidity results in a large increase in the Index). The modified version of the Chandler Burning Index is computed from:

CBI = (((110 - 1.373*RH) - 0.54 * (10.20 - T)) * (124 * 10**(-0.0142*RH)))/60

where

RH = forecast monthly mean afternoon relative humidity (percent)

T = forecast monthly mean afternoon temperature (degrees Celsius)

The Chandler Burning Index has been shown to be highly correlated with monthly fire activity.