Modelling the probability of sustained flaming: predictive value of fire weather index components compared with observations of site weather and fuel moisture conditions

2007 ◽  
Vol 16 (2) ◽  
pp. 161 ◽  
Author(s):  
Jennifer L. Beverly ◽  
B. Mike Wotton

We investigated the likelihood that short-duration sustained flaming would develop in forest ground fuels that had direct contact with a small and short-lived flame source. Data from 1027 small-scale experimental test fires conducted in field trials at six sites in British Columbia and the North-West Territories between 1958 and 1961 were used to develop logistic regression models for ten fuel categories that represent unique combinations of forest cover, ground fuel type, and in some cases, season. Separate models were developed using two subsets of independent variables: (1) weather variables and fuel moisture measurements taken at the site of the test fire; and (2) Canadian Fire Weather Index (FWI) system components calculated from weather observations recorded at a nearby station. Results indicated that models developed with FWI system components were as effective as models developed with site variables at predicting the probability of short-duration sustained flaming in most fuel categories. FWI system components were not useful for predicting sustained flaming in spring grass fuels and had limited usefulness for modelling the probability of sustained flaming in aspen leaf ground fuels during summer conditions. For all other fuel categories, FWI system components were highly effective substitutes for site variables for modelling the probability of sustained flaming.

2004 ◽  
Vol 13 (4) ◽  
pp. 391 ◽  
Author(s):  
B. D. Amiro ◽  
K. A. Logan ◽  
B. M. Wotton ◽  
M. D. Flannigan ◽  
J. B. Todd ◽  
...  

Canadian Fire Weather Index (FWI) System components and head fire intensities were calculated for fires greater than 2 km2 in size for the boreal and taiga ecozones of Canada from 1959 to 1999. The highest noon-hour values were analysed that occurred during the first 21 days of each of 9333 fires. Depending on ecozone, the means of the FWI System parameters ranged from: fine fuel moisture code (FFMC), 90 to 92 (82 to 96 for individual fires); duff moisture code (DMC), 38 to 78 (10 to 140 for individual fires); drought code (DC), 210 to 372 (50 to 600 for individual fires); and fire weather index, 20 to 33 (5 to 60 for individual fires). Fine fuel moisture code decreased, DMC had a mid-season peak, and DC increased through the fire season. Mean head fire intensities ranged from 10 to 28 MW m−1 in the boreal spruce fuel type, showing that most large fires exhibit crown fire behaviour. Intensities of individual fires can exceed 60 MW m−1. Most FWI System parameters did not show trends over the 41-year period because of large inter-annual variability. A changing climate is expected to create future weather conditions more conducive to fire throughout much of Canada but clear changes have not yet occurred.


2008 ◽  
Vol 17 (3) ◽  
pp. 328 ◽  
Author(s):  
A. Carvalho ◽  
M. D. Flannigan ◽  
K. Logan ◽  
A. I. Miranda ◽  
C. Borrego

The relationships among the weather, the Canadian Fire Weather Index (FWI) System components, the monthly area burned, and the number of fire occurrences from 1980 to 2004 were investigated in 11 Portuguese districts that represent respectively 66% and 61% of the total area burned and number of fires in Portugal. A statistical approach was used to estimate the monthly area burned and the monthly number of fires per district, using meteorological variables and FWI System components as predictors. The approach succeeded in explaining from 60.9 to 80.4% of the variance for area burned and between 47.9 and 77.0% of the variance for the number of fires; all regressions were highly significant (P < 0.0001). The monthly mean and the monthly maximum of daily maximum temperatures and the monthly mean and extremes (maximum and 90th percentile) of the daily FWI were selected for all districts, except for Bragança and Porto, in the forward stepwise regression for area burned. For all districts combined, the variance explained was 80.9 and 63.0% for area burned and number of fires, respectively. Our results point to highly significant relationships among forest fires in Portugal and the weather and the Canadian FWI System. The present analysis provides baseline information for predicting the area burned and number of fires under future climate scenarios and the subsequent impacts on air quality.


1988 ◽  
Vol 18 (1) ◽  
pp. 128-131 ◽  
Author(s):  
R. Trowbridge ◽  
M. C. Feller

Unsuccessful attempts to ignite slash resulting from the mechanical knocking down of lodgepole pine in west central British Columbia led to a short-term investigation of the relationship between the Fine Fuel Moisture Code of the Canadian Forest Fire Weather Index System and the moisture content of various fine fuel components <1 cm in diameter. Of the types of fuel sampled, the moisture contents of B.C. Forest Service fuel moisture sticks and aged slash were similar to, and well correlated (r = 0.79 and 0.81, respectively) with, the equivalent moisture content calculated from the Fine Fuel Moisture Code. The Fine Fuel Moisture Code was not designed to relate to the moisture content of uncured fuels. Thus, the moisture contents of fresh living slash (material from knocked down trees still attached to living roots) and of fresh dead slash (material unattached to living trees that had not yet experienced a complete fire season in which to fully cure) were poorly correlated with moisture content (r = 0.16 and 0.42, respectively). The moisture content of the progressively curing, needle-bearing fresh dead slash was relatively high at the beginning of the fire season, but became similar to the moisture content during the first half of July. This suggests that the Fine Fuel Moisture Code can also be used to predict the moisture content of such fine slash after these fuels have cured for approximately 3 months during the snow-free period.


2018 ◽  
Vol 42 (3) ◽  
Author(s):  
Fillipe Tamiozzo Pereira Torres ◽  
Gumercindo Souza Lima ◽  
Bráulio Furtado Alvares

ABSTRACT The objective of this study was to evaluate the performance of different fire hazard indices (FWI, FMA, FMA+, Telicyn, Nesterov, P-EVAP and EVAP/P), taking into account the fire behavior variables and the susceptibility to fire expressed by the moisture of the combustible material. For this purpose, controlled burnings were performed at different times and information was recorded in relation to the meteorological conditions, characteristics of the combustible material and fire behavior variables. In general, all the indices presented significant correlations with both the moisture of the combustible material and the behavior of the fire. However, in general, a higher linear correlation of components of the Canadian Fire Weather Index (FWI) system was observed in predicting fire behavior and EVAP / P index in fuel moisture. The consistency of the correlations between the various indices and the analyzed variables makes the methodology possible to be used in any place, facilitating the decision making in regions where records of occurrences of forest fires are absent or unreliable.


1984 ◽  
Vol 14 (1) ◽  
pp. 68-76 ◽  
Author(s):  
Albert J. Simard ◽  
James E. Eenigenburg ◽  
Richard W. Blank

Observed jack pine (Pinusbanksiana Lamb.) slash moisture was compared with U.S. National Fire-Danger Rating System (NFDRS) and Canadian Fire Weather Index (FWI) predictions. The NFDRS models underestimated wood and foliage moisture; the FWI models overestimated wood moisture but were accurate for foliage moisture. Differences in predictive accuracy between the two sets of regression equations were not significant. The NFDRS equations were somewhat more data dependent, however, and their residuals tended to be biased. Significant differences in moisture profiles were noted among three fuel size classes, between fuels with and without bark, and between litter and needles. Differences between fuels on the ground and above the ground were not significant. The results should be applicable to most fuels influenced by moist climates.


1982 ◽  
Vol 12 (4) ◽  
pp. 1028-1029 ◽  
Author(s):  
Martin E. Alexander

The characteristics and short-term results of experimental prescribed fires in 2-year-old trembling aspen (Populustremuloides Michx.) logging slash in northern Minnesota have been described by D. A. Perala (1974. Can. J. For. Res. 4: 222–228). The associated burning conditions are expressed here in terms of the weather-dependent numerical fuel moisture codes and fire behavior indexes of the Canadian system of forest fire danger rating.


2018 ◽  
Vol 28 (1) ◽  
pp. 432
Author(s):  
Benjamin Leonardo Alves White

O presente artigo busca descrever, por meio de uma revisão da literatura, os principais modelos matemáticos existentes para estimar o teor de umidade dos materiais combustíveis florestais finos e mortos, ou seja, os materiais da classe de 1-h de timelag, com base em variáveis meteorológicas. A determinação desses valores compreende uma importante informação para o delineamento de ações de prevenção e combate a incêndios florestais, e de realização de queimadas controladas, já que respondem pela probabilidade de ignição e comportamento do fogo. Com base na análise realizada, percebe-se que o Fine Fuel Moisture Code (FFMC), um dos componentes do Fire Weather Index (FWI) canadense, constitui o modelo de previsão do teor de umidade mais utilizado no mundo. Porém, considerando-se que trabalhos na literatura relatam limitações e imprecisão tanto no FFMC quanto nos demais modelos analisados nesse artigo, é essencial a validação dos mesmos antes de serem utilizados de forma operacional. Em função da pequena quantidade de estudos envolvendo essa temática no Brasil, recomenda-se a validação ou desenvolvimento de novos modelos, a fim de se aprimorar os programas de prevenção e de delineamento de risco de incêndios florestais em nível nacional.


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