Changes in the large fire seasons induced by climate variability may have implications in several sectors of modern society. This communication aims to investigate possible changes in the behaviour of active fires during the wintertime and document an event that occurred in the transboundary mountainous region in the north-western Iberian Peninsula between Portugal and Spain on 28 January 2022. The VIIRS active fire data, a satellite product, were analysed for the period between December 2012 and February 2022. The Meso-NH model was used to explore the atmospheric conditions during the event that burned almost 2400 ha. It was configured in a single domain with a horizontal resolution of 1500 m (300 × 300 grid points). The study highlights an increase in fire occurrence during the winter of 2021/22 and indicates that climate variability may create atmospheric conditions propitious for fire development even during the winter. The mild temperatures, dry air, and easterly flow affecting northern Portugal played an important role in the fire that occurred on 28 January 2022. Local orographic effects associated with downslope flow favoured fire propagation. Given the lack of knowledge about large winter fires, this study can be a starting point for future research on this subject.

Increased knowledge of the meteorological conditions that lead to mega-fires is important to prevent wildfires and improve firefighting. This study analyses the atmospheric conditions that led to the largest forest fire ever observed in Portugal in 2019. The fire burned an estimated total area of around 9000 hectares in 12 h. The study is based on two simulations performed with the Meso-NH atmospheric model. The control simulation was configured in a single and large domain with 2500 m resolution, whereas a second simulation was configured using the grid nesting technique with an inner domain with 500 m resolution. The fire developed under typical summer conditions, under the influence of the Azores anticyclone and the presence of the Iberian thermal low. The weather pattern included intense northwest winds in the western region of the Iberian Peninsula. In the fire area, the wind speed was around 7 m s⁻¹ with maximum wind gusts of 15 m s⁻¹, favouring the rapid spread of the fire and characterising the event as a wind-driven fire. This study demonstrates the benefits of the use of large domains and high-resolution numerical simulations to explore the regional and local effects, which are crucial for the evolution of some fires.

This is an exploratory study aiming to assess the fire risk perception by operators of the Vale do Guadiana Natural Park (PNVG), southern Portugal. To maximize the sample size, a questionnaire survey was distributed among 35 entities with activities in tourism, hunting, and agriculture, as well as among members of PNVG’s co-management commission. For data analysis and interpretation, quantitative and qualitative analyses were used. Survey responses revealed that the entities expressed concern about and made efforts toward the search for and improvement in mitigation strategies in the occurrence of fires. A total of 69.6% of the respondents have knowledge of the occurrence of fires in the region. The qualitative analysis highlights the concern with biodiversity, as well as with the maintenance and cleaning of the PNVG. This study verifies the degree of importance that the tourism sector should give to the impacts caused by fires. The impact of climate change favoring fires was recognized by the entities, as well as the fact that the loss of biodiversity due to fires may have a direct impact on the attractiveness of this tourist destination, indicating the importance of environmental conservation strategies for the region.

This study provides insights into large fires in the Pantanal by analyzing the atmospheric conditions that influenced the rapid fire evolution between 13 and 14 November 2023, when fire fronts spread rapidly, leading to critical situations for firefighters. The observation-based analysis helped us to identify some characteristics of the fire’s evolution and the meteorological conditions in the region. Furthermore, two simulations were run with the Meso-NH model, which was configured with horizontal resolutions of 2.5 km and 5 km. The fire behavior, characterized by satellite observations, revealed periods with a sudden increase in active fire numbers. High temperatures and low relative humidity in the region characterized the fire weather conditions. The simulations confirmed the critical fire condition, showing the benefits of increasing the resolution of numerical models for the Pantanal region. The convection-resolving simulation at 2.5 km showed the repeated development of gust fronts in the late afternoon and early evening. This study highlights this dynamic that, coupled with intense surface wind gusts, was crucial for the intensification of the fire spread and unexpected behavior. This study is a first step toward better understanding fire dynamics in the Pantanal through atmospheric modeling, and it can support strategies for firefighting in the region.

A major fire occurred in the wildland–urban interface in southern Portugal, on 13 July 2022, becoming uncontrolled due to weather conditions. This study investigates how atmospheric dynamics increased fire danger in Mainland Portugal during early July 2022. The synoptic circulation from European Centre for Medium-Range Weather Forecasts (ECMWF) analysis and mesoscale conditions from Meso-NH model simulation at 1.5 km resolution revealed atmospheric conditions before and during the fire. Fire risk was assessed using the Fire Weather Index (FWI) from Meso-NH outputs. A blocking pattern was configured by an upper-level low-pressure system in early July, remaining semi-stationary west of Mainland Portugal until 18 July. The counter-clockwise circulation of the cut-off low resulted in dry, warm air advection from North Africa, enhancing fire danger over the Iberian Peninsula. In southern Portugal, a jet-like wind with strong east/southeasterly flow from Gibraltar Strait favored rapid fire spread. This circulation below 1 km altitude from the Mediterranean Sea enhanced fire danger through strong winds, independent of the large-scale blocking pattern. This study presents an atmospheric scenario for evaluating fire danger in Southern Portugal, important for pre-firefighting management that complemented previous studies for the region. Also, high-resolution FWI calculations using Meso-NH emphasized the importance of improved temporal and spatial resolution for fire danger assessment.

The study discusses in an exploratory way the atmospheric conditions leading to several fires in the Pantanal on November 12, 2023. These episodes were marked by two periods of maximum fire expansion, first in the early afternoon and another in the evening. The study is based on a set of observations from satellites and weather stations, which helped to identify these fires and some meteorological conditions at the surface. In addition, the Fire Weather Index (FWI) in the Pantanal was analyzed for a 44-year period. However, this dataset was not enough to completely explain the fire behavior on that day. In this context, atmospheric modeling was applied to find the possible causes of fire behavior in these two periods. The Meso-NH model was run with two nested domains of horizontal resolutions of 2500 m and 500 m. The results showed a positive trend of FWI in the last decades and a clear seasonality for the maximum values in 2023. Also, the simulation indicated favorable weather conditions for fire ignition, given the high temperatures and low relative humidity. However, the wind gust field showed moderate gusty winds in both periods but caused by different forces. In the early afternoon, the larger scale circulation favored fire propagation, whereas in the evening fire spread by a gust front. Furthermore, the findings highlight the role of weather conditions on a sub-daily scale, with sudden changes in surface winds throughout the day, which is strongly recommended to be considered when examining fire danger and firefighting action plans in the region.