National Fire Danger Rating System

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1 The National Fire Danger Rating System
2 References

[edit] The National Fire Danger Rating System

[edit] Background

John J. Keetch, caca a fire researcher in the southeast, wrote:

"One of the prime objectives of the National Fire Danger Rating System (NFDRS) is to provide as accurate a measure as possible of the relative seriousness of burning conditions and thereby, NFDRS can serve as an aid to fire control programs."

When work started in 1968 on the NFDRS a framework was constructed. A philosophy had to be adopted in order to allow the development of the system to proceed. NFDRS provides a uniform consistent system that possesses standards which agencies with wildfire suppression responsibility can apply and interpret.

[edit] Basic assumption

NFDRS characterizes expected burning conditions for areas of 10,000 to 100,000 acres (40 to 400 km²). The system is low on the scale of resolution.

Considers initiating fires only.
Considers containment as opposed to extinguishment.
Relates contaiment job to flame length.
The ratings are to be interpretable and meaningful
Ratings are to be used in combination.
Ratings are to be linear and relative.
Ratings between fuel models are comparable.
Ratings are for the worst case in the Fire Danger Rating Area.

[edit] NFDRS structure

NFDRS is a complex set of equations that use user defined constants and measured variables to calculate daily indices and components that can be used for decision support.

[edit] The outputs

The output section of the NFDRS Structure chart is the components or simply the outputs that are based in fire behavior description, but expressed in the broader context of fire danger rating.

1. Spread Component (SC) - Displays a value numerically equivalent to the predicted forward rate of spread of a head fire in feet per minute. The SC is a function of fuel model characteristics, live fuel moistures, the 0 to 3 inch dead fuel moisture (heavily weighted to the 1-hour timelag fuels), wind speed and slope class. The SC is highly variable due to the effects of relative humidity, wind and live fuel moisture.

2. Ignition Component (IC) - Displays the probability of a firebrand causing an ignition requiring a suppression action.

[edit] References

This article or section includes a list of references or external links, but its sources remain unclear because it lacks in-text citations.
You can improve this article by introducing more precise citations.

Keetch, John J; Byram, George. 1968. A drought index for forest fire control. Res. Paper SE-38. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 32 pp. (Revised 1988).
Burgan, Robert E. 1988. 1988 revisions to the 1978 National Fire-Danger Rating System. Res. Pap. SE-273. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 39 pp.
Burgan, R.E.; Hardy, C.C.; Ohlen, D.O.; Fosnight, G.; Treder, R. 1999. Ground sample data for the national land cover characteristics database. United States Department of Agriculture, Forest Service, General Technical Report RMRS-GTR-41, Rocky Mountain Research Station,Ogden, Utah. 12 pages.
Burgan, R.E.; Hartford, R.A. 1993. Monitoring vegetation greenness with satellite data. United States Department of Agriculture, Forest Service, General Technical Report INT-297, Intermountain Forest and Range Experiment Station, Ogden, Utah. 13 pages.