Wildfire danger indicates the likelihood that a fire ignites and propagates in a certain area and period. Even though most natural hazard terminologies name this component as Hazard (see Short Definitions), Danger is more commonly used in the wildfire management community (such as the American, Canadian, Australian, and European systems) to indicate a similar concept. Danger assessment considers human and natural causes leading to a fire ignition, as well as those factors that must be present to start a fire or affect fire behaviour, including fuel availability and moisture status, slope and weather conditions.
Fire ignition can be divided into human and natural ignitions, defined according to the main fire causes. Prestemon et al. (2005)[1] differentiated between two broader categories of fire causes: natural (basically referring to lightning) and anthropocentric, the latter of which was further divided into accidental and intentional. However, since the statistics on causes are not widely available, human ignitions are generally considered as a single category.
Fire propagation is closely related to fire spread, but these terms are not fully identical. They both refer to the likelihood or probability that fire will spread in a particular direction or over a specific area, along with information about the intensity and speed of fire spread. Fire spread depends on weather, terrain, fuel conditions and on fire dynamics, where these conditions represent either current, historical or possible future scenarios. Propagation potential provides a more general understanding of the target area and conditions prevailing in that zone [2] [3]. These conditions can be observed through shorter or longer time periods (ranging from 1 hour to even decades).
A variety of fire danger systems are used in many parts of the world to integrate meteorological and fuel information into a single or small number of measures [4]. These measures can then be applied to regions to issue warnings, or more locally to estimate the suppression difficulty of a single fire or fire complex [4:1].
The primary fire danger systems, usually used in fire prevention and assessment plans around the world, are:
Return to Conceptual Framework Diagram
Prestemon, J.P., & Butry, D.T. (2005). Time to Burn: Modeling Wildland Arson as an Autoregressive Crime Function. American Journal of Agricultural Economics, 87, 756-770. ↩︎
Rothermel, R.C. (1972). A Mathematical Model for Predicting Fire Spread in Wildland Fuels. Ogden, Utah: USDA, Forest Service. Research Paper INT-115. ↩︎
Rothermel, R.C. (1983). How to predict the spread and intensity of forest and range fires. Ogden, UT: USDA, Forest Service, GTR INT-143. ↩︎
Dowdy, A.J., Finkele, K., Mills, G.A., & de Groot, W. (2009). Australian fire weather as represented by the McArthur Forest Fire Danger Index and the Canadian Forest Fire Weather Index. CAWCR Technical Report No 10, Centre for Australian Weather and Climate Research: Docklands, Victoria, Australia. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Van Wagner, C.E. (1987). Development and Structure of the Canadian Forest Fire Weather Index System. Forestry, 51, Article No. 3. ↩︎
NWCG. (2024). Fire Danger Background. In: Fire Behavior Field Reference Guide - PMS 437, https://www-nwcg.fs2c.usda.gov/publications/pms437/fire-danger/fire-danger-background. ↩︎ ↩︎
McArthur, A.G. (1967). Fire behaviour in eucalypt forests. For. Timb. Bur. Aust., Leaf. No. 107, 25 pp. ↩︎
Deeming, J.E., Burgan, R.E., & Cohen, J.D. (1977). National Fire-Danger Rating System - 1978. General Technical Report INT-GTR-39. Ogden, UT: USDA Forest Service, Intermountain Forest and Range Experiment Station, 63 p. ↩︎
Bradshaw, L.S., Deeming, J.E., Burgan, R.E., & Cohen, J.D. (1984). The 1978 National Fire-Danger Rating System: technical documentation. General Technical Report INT-169. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 44 p. ↩︎
USDA/Forest Service. (2023). National Fire Danger Rating System, https://www.fs.usda.gov/detail/htnf/home/?cid=stelprdb5173311. ↩︎