The National Fire Danger Rating System (NFDRS) is comprised of a of combination of computer programs and algorithms to estimate fire danger for a given area within a 24 hour period of time. Fire danger is derived from determining the upper limit of fire behavior in an area for a 24 hour period based upon fuels, topography, and weather.
The NFDRS serves as a guide from which agencies can determine the use of pre-suppression activities, or select the appropriate level of response to a reported wildfire in the absence of the other information.
For historical background, system structure, and more in depth information on the NFDRS click the following link: http://www.wfas.net
Source: US Forest Service Rocky Mountain Research Station. Wildland Fire Assessment System NFDRS Fuel Model Map. Accessed on 9 September 2013. Available at http://www.wfas.net