•Numerous wildfire danger indices are available for use in calculating wildfire danger ratings.•Four wildfire danger indices are studied: Fire Weather Index (FWI), Keetch-Byram Drought.•Index (KBDI), ...Fosberg Fire Weather Index (FFWI), Nesterov Index.•The relative predictive qualities of these four wildfire danger indices is investigated with a.•Focus on their functionality in northern Europe, particularly in Sweden.•Three of the indices using cumulative weather data were found to perform best, i.e. FWI,
Wildfire danger indices, or fire danger rating systems, are widely used to inform decision-making related to wildfire risk management. Several studies have compared different indices’ performance; however, results have shown that this varies in different parts of the world. Further, many of these indices have not yet been assessed for Swedish conditions. In this study, four different weather-based wildfire danger indices have been investigated by comparing their performance in predicting wildfire activity when applied to Swedish conditions. Daily index values were calculated for seven Swedish geographical regions during 2018, a year with high wildfire activity. The aim of the study has been to rank the ability of the methods to predict wildfire danger in Sweden which is why a single year with high fire frequency has been chosen as the “test year”. The daily index values were compared to wildfire incident data, i.e.: fire and rescue service personnel hours spent on a fire, total burned area, and number of daily fire ignitions. Kendall’s Taub correlation coefficient was calculated for each index and wildfire data in the seven regions. The indices were then ranked based on the strength of the correlation. It was found that three of the indices (those based on cumulative weather data) exhibited a significantly higher correlation with wildfire activity than the fourth index. Further, the Fire Weather Index, developed in Canada and currently used in Sweden, was identified as a good choice for Swedish conditions when compared to the three other indices.
•We investigate the relationship between burned area and fire-weather for the entire globe, focusing on the fire season the grid-box scale.•A large proportion of total global land area exhibited a ...significant relationship between fire weather index (FWI) and burned area.•The most sensitive areas to fire weather fluctuations are those with a FWI below 17, like tropical moist and temperate broadleaf forests and also boreal forests and taigas.•We calculated near-future FWI scenarios (2026–2045) using an ensemble of state-of-the-art Earth System Models from the CMIP5 database.•Projected FWI anomalies for the most sensitive biomes are either negative or close to zero, although positive increments in some regions may result in significant disruptions in fire regimes in boreal and Amazon rain forest among others.
Fire is an integral Earth system process, playing an important role in the distribution of terrestrial ecosystems and affecting the carbon cycle at the global scale. Fire activity is controlled by a number of biophysical factors, including climate, whose relevance varies across regions and landscapes. In light of the ongoing climate change, understanding the fire–climate relationships is an issue of current interest in order to identify the most vulnerable regions. Building upon recent global observations of burned areas and climate, we investigate the sensitivity of fire activity to fire–weather across the world's major biomes. We identify the biomes susceptible to inter-annual fire–weather fluctuations, unveiling a non-linear relationship with a saturation threshold past which the area burned can be considered insensitive to increasing fire-weather. Our results depict an unambiguous spatial pattern that identifies the world regions where short-term climate fluctuations are unlikely to produce any significant effect on current fire activity, and those most sensitive to fire-weather changes. In particular, the boreal forests and extensive areas of tropical and subtropical moist broadleaf forests (excluding Africa) as well as sizeable areas of temperate broadleaf forests are identified as highly sensitive. We then present near-future fire-weather scenarios (period 2026–2045) using a state-of-the-art ensemble or Earth System Models (ESMs) from the CMIP5 database, considering a moderate and a high emission scenario (RCPs 4.5 and 8.5). The projected anomalies in fire-weather for the vulnerable temperate biomes are small in magnitude and their direction is either negative or just slightly positive, although significant differences in the projected probability density functions suggest that disruptions of fire regimes may occur locally. Other sensitive ecosystems, like the rain forests of the Amazon basin may experience a significant increment in fire-weather that may result in severe impacts on fire regimes as a direct consequence of climate change in the next decades.
•A novel strategy for managing wildfires and blackouts using microgrids is proposed.•The Fire Weather Index is used to describe the fire risk distribution in a grid.•The Grid and Wildfire Index are ...linked by line locations and fire risk distribution.•Set Victoria Australia as a case study, 68% of the overall system cost can be saved.
This paper proposes a strategy for managing wildfire risks and preventing blackouts using microgrids. To demonstrate this approach, not seen in previous literature, we use the power network of Victoria, Australia, in December 2019 as a case study. The Fire Weather Index (FWI) is a crucial indicator of global fire behaviour both spatially and temporally, as proved with its robust analysis within many previous studies. The FWI is applied to a Wildfire-Energy System for the first time, contributing to a higher spatial and temporal resolution to position the wildfire risk in a grid. A novel method is proposed to automatically correlate the wildfire risk index and the power network model using geographical information of the transmission lines. The optimal power flow and grid performances are obtained from a grid model which incorporates wildfire risk distributions. It is shown that a system with installed microgrids can maintain operation under severe fire-related conditions without scheduled or unplanned outages. Finally, a cost-benefit analysis is conducted, which demonstrates that 68% of system costs can be recuperated by implementing networked microgrid solutions.
Studies and observations have pointed out that recent wildfires have been more severe and burned area is increasing in tropical regions. The current study aims at investigating the influence of ...oceanic climate modes and their teleconnection on global fire danger and trends in the 1980–2020 interval. Disentangling these trends demonstrates that across the extratropics they are primarily related to increases in temperature, whereas in the tropics changes in short-term precipitation distribution dominates the trends. Moreover, the environmental impact of short-term precipitation is dependent on local vegetation type and tightly related to oceanic temperatures far from the burned areas. Indeed, in the 2001–2020 period, a warmer tropical North Atlantic was associated with more fires in the Amazon and Africa, whereas ENSO has weakened the fire activity in equatorial Africa. The remarkable impact of oceanic modes of climate variability in inducing environmental conditions conducive to fires, has particular relevance for the seasonal spatiotemporal wildfire forecasts. Although local aspects are crucial for fire management, long-term predictions should take into account the behavior of potential climate drivers located far from the region of interest. Such teleconnections can be identified ahead of local weather anomalies.
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•Global wildfires incidence is tightly dependent on Atlantic SST.•Maximum PFI matches 80 % of observed fires.•Fire impact of short-term precipitation is dependent on local vegetation.
•We compared landscape controls of fire size and fire severity.•Fire weather exerted strong influences on fire size.•Vegetation is the dominating control of fire severity.•Driving mechanisms of these ...two attributes possess different scale dependence.•Fire size and fire severity may have inconsistent responses to climate warming.
Fire size and fire severity are two crucial parameters for describing fire regimes that reflect spatial heterogeneities of fire spread behavior and its interaction with the environment. Determining how environmental controls regulate these two metrics of the fire regime is of critical importance for predicting response of fire to climate change and designing strategic fire management plans. Here, we evaluated influences and relative contributions of fire weather, topography, and vegetation on fire size and fire severity in a Chinese boreal forest ecosystem. We also compared how relative contributions vary along a continuous gradient of spatial scales using a moving-window resampling approach. Results showed fire weather was the dominant driving factor for fire size, while vegetation and topography exerted stronger influences on fire severity. Such relative influences on fire size and fire severity possessed different scale dependence. For fire size, small burns (<130ha) were mainly constrained by vegetation as it accounted for nearly 43% relative importance, but larger burns (>200ha) were more strongly influenced by extreme fire weather conditions, which accounted for more than 50% relative importance. In contrast, the relative importance of fire weather on fire severity was always less than 20% across the entire range of spatial scales, while relative contributions of vegetation were relatively stable and always greater than 45%. Our study suggests that fuel treatments may have little effect on reducing fire size in boreal forests, but may function to mitigate the severity of future fires. Vegetation type and terrain conditions are important factors to consider for improving efficiency of fuel management.
•Fuel aridity and high-risk fire weather have increased substantially since 1956•The trends are more severe during April-June and linked to the climate change•Fuel aridity levels explain 70% of ...interannual variability in number of wildfires•Marked increase in wildfire-conducive conditions is expected by 2050•Forested areas above 500 m asl. are expected to see largest increases
The occurrence of major wildfires in countries such as Portugal, Italy and Spain (2017) and Sweden (2018) indicated that wildfires pose a risk across Europe. While Central Europe has not been at the center of such events, observed climate data and climate projections suggest a tendency toward more years with wet and warm winters and dry and hot summers as well as fuel accumulation, leading to more hazardous conditions. Although some existing studies analyzed the differences in wildfire occurrence in this territory based on terrain, soil or vegetation characteristics, the effects of climate change have not been properly appraised. To fill this knowledge gap, we used and tested an ensemble of nine fuel aridity metrics, including three dedicated fire danger rating indices, and evaluated their level of agreement with actual fire occurrence, their ability to explain the interannual variability in wildfire frequency, and their temporal trends. The analysis covered the entire territory of the Czech Republic at 500 m spatial resolution. Two periods were included based on observed (1956–2015) and projected (2020–2100) meteorological data using ensembles of five regional climate models (RCMs) and five global circulation models (GCMs) based on Euro-CORDEX and CMIP5 datasets. For the future, we considered Representative Concentration Pathway (RCP) 4.5. Our results showed that since 1956, most of the Czech territory has exhibited an increasing frequency of fire weather days (i.e., days with highly conducive wildfire conditions) and an increasing area affected by weather conducive to wildfire occurrence, with the trends accelerating after 2000. The annual variation in the fuel aridity levels (derived solely from meteorological data) explained more than 2/3 of the reported wildfire variability during 1991–2015 over the Czech Republic. The future projections based on the RCM or GCM ensembles indicated a significant increase in fuel aridity and an increase in the area under fire-conducive conditions. Recommendations derived from such robust results are provided for stakeholders seeking to implement adaptation measures.
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Heat stress and forest fires are often considered highly correlated hazards as extreme temperatures play a key role in both occurrences. This commonality can influence how civil protection and local ...responders deploy resources on the ground and could lead to an underestimation of potential impacts, as people could be less resilient when exposed to multiple hazards. In this work, we provide a simple methodology to identify areas prone to concurrent hazards, exemplified with, but not limited to, heat stress and fire danger. We use the combined heat and forest fire event that affected Europe in June 2017 to demonstrate that the methodology can be used for analysing past events as well as making predictions, by using reanalysis and medium-range weather forecasts, respectively. We present new spatial layers that map the combined danger and make suggestions on how these could be used in the context of a Multi-Hazard Early Warning System. These products could be particularly valuable in disaster risk reduction and emergency response management, particularly for civil protection, humanitarian agencies and other first responders whose role is to identify priorities during pre-interventions and emergencies.
•Overestimating the correlation between heat stress and forest fires danger could lead to underestimating potential impact.•A simple methodology to map areas prone to concurrent hazards, using layers designed for Multi-Hazard Early Warning Systems.•These layers could be particularly valuable in disaster risk reduction and emergency response management.
•Models that are successful in predicting fire danger may fail to identify days with large fire.•Multi-variable models yield better results than single-variable models.•Multi-variable meteorological ...models performed similarly to single-variable fire weather models.•The role of modeling approach was related to the region being modeled or the input variable groups.
Fire indices are used to describe the weather conditions that influence fire ignition and fire behavior. Although many studies analyzed their performance on fire occurrence at daily resolution, few focused on their ability to capture the burned area, which is usually analyzed at the weekly or monthly scale. Cumulative Logarithmic Area Ranking Efficiency (CLARE) is a newly developed metric that takes burned area into account when assessing daily fire danger. The use of CLARE in addition to the Area Under the receiver operating characteristic Curve (AUC) in the selection process of fire indices or fire occurrence models provides a complementary metric that allows for the evaluation of a model's ability to assess burned area. We evaluated the CLARE performance in 11 regions ranging from the European Alps to the Mediterranean basin. We also assessed the impact of (i) different groups of input variables (meteorological variables vs. fire indices), (ii) model complexity in terms of number of variables, and (iii) the modeling approach (Generalized Linear Models vs. Maxent) on the performance of CLARE. We found that models that achieve a high AUC for predicting fire occurrence may fail to show a high performance when predicting burned area. Using a multi-variable modeling approach is likely to provide higher CLARE performance than using single-variable fire index models, especially among models that have high AUC. Moreover, using this approach led to better multi-variable meteorological model performance than single-variable fire index models for some regions. This may be particularly valuable for regions where the calculation of fire indices is not possible. Finally, the differences between the modeling approaches were mainly related to the region or input variable groups. Overall, our results highlight that including burned area in the fire danger assessment process is feasible across a wide range of environmental conditions and provides valuable insights.
► Future wildfire potential will increase overall in the continental U.S. ► Fire season could become a few months longer. ► The warming trend is a major contributor to the fire potential increase. ► ...Fire potential has been increasing in recent decades.
This study investigates trends in wildfire potential in the continental United States under a changing climate. Fire potential is measured by the Keetch–Byram Drought Index (KBDI), which is determined by daily maximum temperature and precipitation. The impact of relative humidity and wind speed is examined by comparing KBDI with the modified Fosberg Fire Weather Index (mFFWI). The present (1971–2000) and future (2041–2070) daily regional climate conditions were obtained by dynamical downscaling of the HadCM3 global projection using HRM3 regional climate model provided by the North America Regional Climate Change Assessment Program (NARCCP). It is shown that fire potential is expected to increase in the Southwest, Rocky Mountains, northern Great Plains, Southeast, and Pacific coast, mainly caused by future warming trends. Most pronounced increases occur in summer and autumn. Fire seasons will become longer in many regions. The future fire potential increase will be less pronounced in the northern Rocky Mountains due to the changes in humidity and wind. Present fire potential is found to have been increasing across continental U.S. in recent decades. The future KBDI increase in the central Plains and the South projected using the HadCM3–HRM3 climate change scenario is smaller than the increases using the climate change scenarios from most of other NARCCAP model combinations. Larger inter-seasonal and inter-annual fire potential variability is expected in the future in the Pacific and Atlantic coastal regions. The projected increases in wildfire potential for many regions of the U.S. suggest that increased resources and management efforts for disaster prevention and recovery would be needed in the future.
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