Fire weather index system components for large fires in the Canadian boreal forest

2004 ◽  
Vol 13 (4) ◽  
pp. 391 ◽  
Author(s):  
B. D. Amiro ◽  
K. A. Logan ◽  
B. M. Wotton ◽  
M. D. Flannigan ◽  
J. B. Todd ◽  
...  
Keyword(s):  
Weather Conditions ◽  
Fire Season ◽  
Fire Weather ◽  
Fuel Moisture ◽  
Weather Index ◽  
Fire Weather Index ◽  
System Parameters ◽  
System Components ◽  
Large Fires ◽  
Canadian Boreal Forest

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.

What are the drivers of dangerous fires in Mediterranean France?

2018 ◽  
Vol 27 (3) ◽  
pp. 155 ◽  
Author(s):  
S. Lahaye ◽  
T. Curt ◽  
T. Fréjaville ◽  
J. Sharples ◽  
L. Paradis ◽  
...  
Keyword(s):  
Weather Conditions ◽  
Fire Weather ◽  
Weather Index ◽  
Fire Weather Index ◽  
Quantile Regression Model ◽  
Mediterranean Europe ◽  
Main Driver ◽  
Large Fires ◽  
Strong Winds ◽  
Mediterranean France

Wildfire containment is often very challenging for firefighters, especially for large and rapidly spreading fires where the risk of firefighter entrapment is high. However, the conditions leading to these ‘dangerous’ fires are poorly understood in Mediterranean Europe. Here, we analyse reports and interviews of firefighters over the last 40 years in four regions of south-eastern France and investigate the weather conditions that induce large fires, fast-growing fires and fires that are conducive to entrapment. We adopt a quantile regression model to test the effect of weather conditions across different fire sizes and growth rates. The results show that strong winds drive the largest fires everywhere except in Corsica, the southernmost region, where high temperature is the main driver. Strong winds also drive entrapments whereas high temperatures induce rapidly spreading fires. This emphasises that wind-driven fire is the dominant pattern of dangerous fires in France, but it reveals that large ‘convective’ fires can also present considerable danger. Beyond that, the Fire Weather Index appears to be a good predictor of large fires and fires conducive to entrapments. Identifying weather conditions that drive ‘dangerous’ wildfires will provide useful information for fire agencies to better prepare for adverse fire behaviours.

Relationships between the moisture content of fine woody fuels in lodgepole pine slash and the Fine Fuel Moisture Code of the Canadian Forest Fire Weather Index System

1988 ◽  
Vol 18 (1) ◽  
pp. 128-131 ◽  
Author(s):  
R. Trowbridge ◽  
M. C. Feller
Keyword(s):  
Moisture Content ◽  
Forest Fire ◽  
Index System ◽  
Lodgepole Pine ◽  
Fire Season ◽  
Fire Weather ◽  
Fuel Moisture ◽  
Weather Index ◽  
Fire Weather Index ◽  
Moisture Contents

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.

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
Keyword(s):  
Short Duration ◽  
Forest Cover ◽  
Field Trials ◽  
Small Scale ◽  
Fire Weather ◽  
Fuel Moisture ◽  
Weather Index ◽  
Fire Weather Index ◽  
North West ◽  
System Components

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.

scholarly journals Attribution of the Australian bushfire risk to anthropogenic climate change

2020 ◽  
Author(s):  
Geert Jan van Oldenborgh ◽  
Folmer Krikken ◽  
Sophie Lewis ◽  
Nicholas J. Leach ◽  
Flavio Lehner ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Southern Annular Mode ◽  
Warming Trend ◽  
Anthropogenic Climate Change ◽  
Fire Season ◽  
Fire Weather ◽  
Weather Index ◽  
Fire Weather Index

Abstract. Disastrous bushfires during the last months of 2019 and January 2020 affected Australia, raising the question to what extent the risk of these fires was exacerbated by anthropogenic climate change. To answer the question for southeastern Australia, where fires were particularly severe, affecting people and ecosystems, we use a physically-based index of fire weather, the Fire Weather Index, long-term observations of heat and drought, and eleven large ensembles of state-of-the-art climate models. In agreement with previous analyses we find that heat extremes have become more likely by at least a factor two due to the long-term warming trend. However, current climate models overestimate variability and tend to underestimate the long-term trend in these extremes, so the true change in the likelihood of extreme heat could be larger. We do not find an attributable trend in either extreme annual drought or the driest month of the fire season September–February. The observations, however, show a weak drying trend in the annual mean. Finally, we find large trends in the Fire Weather Index in the ERA5 reanalysis, and a smaller but significant increase by at least 30 % in the models. The trend is mainly driven by the increase of temperature extremes and hence also likely underestimated. For the 2019/20 season more than half of the July–December drought was driven by record excursions of the Indian Ocean dipole and Southern Annular Mode. These factors are included in the analysis. The study reveals the complexity of the 2019/20 bushfire event, with some, but not all drivers showing an imprint of anthropogenic climate change.

scholarly journals Verification of WRF modelled fire weather in the 2009–10 New Zealand fire season

2014 ◽  
Vol 23 (1) ◽  
pp. 34 ◽  
Author(s):  
C. C. Simpson ◽  
H. G. Pearce ◽  
A. P. Sturman ◽  
P. Zawar-Reza
Keyword(s):  
New Zealand ◽  
Weather Conditions ◽  
Model Error ◽  
Dew Point ◽  
Fire Season ◽  
Fire Weather ◽  
Fire Weather Index ◽  
Wind Speeds ◽  
Air Temperatures ◽  
Weather Stations

The Weather Research and Forecasting (WRF) mesoscale model was used to simulate the fire weather conditions for the 2009–10 wildland fire season in New Zealand. The suitability of WRF to simulate the high-end fire weather conditions for this period was assessed through direct comparison with observational data taken from 23 surface and two upper-air stations located across New Zealand. The weather variables and fire weather indices considered in the verification were the 1200 hours NZST air temperature, relative humidity, wind speed and direction, 24-h rainfall, New Zealand Fire Weather Index (FWI) and Continuous Haines Index (CHI). On observed high-end fire weather days, the model under-predicted the air temperatures and relative humidities, and over-predicted the wind speeds and 24-h rainfall at most weather stations. The results demonstrated that although WRF is suitable for modelling the air temperatures, there are issues with modelling the wind speeds and rainfall quantities. The model error in the wind speeds and 24-h rainfall contributed significantly towards the model under-prediction of the FWI on observed high-end fire weather days. In addition, the model was not suitable for predicting the number of high-end fire weather days at most weather stations, which represents a serious operational limitation of the WRF model for fire management applications. Finally, the modelled CHI values were only in moderate agreement with the observed values, principally due to the model error in the dew point depression at 850hPa.

Fire activity in Portugal and its relationship to weather and the Canadian Fire Weather Index System

2008 ◽  
Vol 17 (3) ◽  
pp. 328 ◽  
Author(s):  
A. Carvalho ◽  
M. D. Flannigan ◽  
K. Logan ◽  
A. I. Miranda ◽  
C. Borrego
Keyword(s):  
Forest Fires ◽  
Daily Maximum ◽  
Fire Weather ◽  
Weather Index ◽  
Fire Weather Index ◽  
Area Burned ◽  
System Components ◽  
Baseline Information ◽  
Forward Stepwise ◽  
Maximum Temperatures

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.

Wildfires and the Canadian Forest Fire Weather Index system for the Daxing'anling region of China

2011 ◽  
Vol 20 (8) ◽  
pp. 963 ◽  
Author(s):  
Xiaorui Tian ◽  
Douglas J. McRae ◽  
Jizhong Jin ◽  
Lifu Shu ◽  
Fengjun Zhao ◽  
...  
Keyword(s):  
Forest Fire ◽  
Forest Fires ◽  
Coniferous Forest ◽  
Northern China ◽  
Fire Danger ◽  
Fire Season ◽  
Fire Weather ◽  
Burnt Area ◽  
Weather Index ◽  
Fire Weather Index

The Canadian Forest Fire Weather Index (FWI) system was evaluated for the Daxing'anling region of northern China for the 1987–2006 fire seasons. The FWI system reflected the regional fire danger and could be effectively used there in wildfire management. The various FWI system components were classified into classes (i.e. low to extreme) for fire conditions found in the region. A total of 81.1% of the fires occurred in the high, very high and extreme fire danger classes, in which 73.9% of the fires occurred in the spring (0.1, 9.5, 33.3 and 33.1% in March, April, May and June). Large wildfires greater than 200 ha in area (16.7% of the total) burnt 99.2% of the total burnt area. Lightning was the main ignition source for 57.1% of the total fires. Result show that forest fires mainly occurred in deciduous coniferous forest (61.3%), grass (23.9%) and deciduous broad leaved forest (8.0%). A bimodal fire season was detected, with peaks in May and October. The components of FWI system were good indicators of fire danger in the Daxing'anling region of China and could be used to build a working fire danger rating system for the region.

scholarly journals A high-resolution reanalysis of global fire weather from 1979 to 2018 – Overwintering the Drought Code

2020 ◽  
Author(s):  
Megan McElhinny ◽  
Justin F. Beckers ◽  
Chelene Hanes ◽  
Mike Flannigan ◽  
Piyush Jain
Keyword(s):  
High Resolution ◽  
Fire Behavior ◽  
Fire Season ◽  
Fire Weather ◽  
Weather Index ◽  
Fire Weather Index ◽  
Start Up ◽  
System Calculation ◽  
Second Procedure ◽  
Temporal Coverage

Abstract. We present a global high-resolution calculation of the Canadian Fire Weather Index (FWI) System Indices using surface meteorology from the ERA5-HRS reanalysis for 1979–2018. ERA5-HRS represents an improved dataset compared to several other reanalyses in terms of accuracy, as well as spatial and temporal coverage. The FWI calculation is performed using two different procedures for setting the start-up value of the Drought Code (DC) at the beginning of the fire season. The first procedure, which accounts for the effects of inter-seasonal drought, overwinters the DC by adjusting the fall DC value with a fraction of accumulated overwinter precipitation. The second procedure sets the DC to its default start-up value (i.e. 15) at the start of each fire season. We validate the FWI values over Canada using station observations from Environment and Climate Change Canada and find generally good agreement (mean Spearman correlation of 0.77). We also show that significant differences in early season DC and FWI values can occur when the FWI System calculation is started using the overwintered versus default DC values, as is highlighted by an example from 2016 over North America. The FWI System moisture codes and fire behavior indices are made available for both versions of the calculation at https://doi.org/10.5281/zenodo.3626193 (McElhinny et al., 2020), although we recommend using codes and indices calculated with the overwintered DC, unless specific research requirements dictate otherwise.

Fire weather thresholds and burnt area in Portugal

2021 ◽  
Author(s):  
Tomás Calheiros ◽  
Akli Benali ◽  
João Neves Silva ◽  
Mário Pereira ◽  
João Pedro Nunes
Keyword(s):  
Land Use ◽  
Cluster Analysis ◽  
Fire Suppression ◽  
Cumulative Effect ◽  
Weather Conditions ◽  
Weather Data ◽  
Fire Weather ◽  
Burnt Area ◽  
Fire Weather Index ◽  
Large Fires

&lt;p&gt;Fire strongly depends on the weather, especially in Mediterranean climate regions with rainy winters but dry and hot summers, as in Portugal. Fire weather indices are commonly used to assess the current and/or cumulative effect of weather conditions on fuel moisture and fire behaviour. The Daily Severity Rating (DSR) is a numeric rating of the difficulty of controlling fires, based on the Canadian Fire Weather Index (FWI), developed to accurately assess the expected efforts required for fire suppression. Recently, the 90th percentile of DSR (90pDSR) was identified as a good indicator of extreme fire weather and well related to the burnt area in some regions of the Iberian Peninsula. The purposes of this work were: 1) to verify if this threshold is adequate for all continental Portugal; 2) to identify and characterize local variations of this threshold, at a higher spatial resolution; and, 3) to analyse other variables that can explain this spatial heterogeneity.&lt;/p&gt;&lt;p&gt;We used fire data from the Portuguese Institute for the Conservation of Nature and Forests and weather data from ERA5, for the 2001&amp;#160;&amp;#8211;&amp;#160;2019 study period. We also used the Land Use and Occupation Charter for 2018 (COS2018), provided by the Directorate-General for Territory, to assess land use and cover in Portugal. The meteorological variables to compute the DSR are air temperature, relative humidity, wind speed and daily accumulated precipitation, at 12 UTC. DSR percentiles (DSRp) were computed for summer period (between 15&lt;sup&gt;th&lt;/sup&gt; May and 31&lt;sup&gt;st&lt;/sup&gt; October) and combined with large (&gt;100 ha) burnt areas (BA), with the purpose to identify which DSRp value is responsible of a large amount of BA (80 or 90%). Cluster analysis was performed using the relation between DSRp and BA, in each municipality of Continental Portugal.&lt;/p&gt;&lt;p&gt;Results reveal that the 90pDSR is an adequate threshold for the entire territory. However, at the municipalities&amp;#8217; level, some important differences appear between DSRp thresholds that explain 90 and 80% of the total BA. Cluster analysis shows that these differences justified the existence of several statistically significant clusters. Generally, municipalities where large fires take place in high or very high DSRp are located in north and central coastal areas, Serra da Estrela, Serra de Montejunto and Algarve. In contrast, clusters where large fires where registered with low DSRp appear in northern and central hinterland. COS2018 data was assessed to analyse if and how the vegetation cover type influences the clusters&amp;#8217; distribution and affects the relationship between DSRp and total BA. Preliminary results expose a possible vegetation influence, especially between forests and shrublands.&lt;/p&gt;

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