Preliminary Analysis of Slope and Fuel Bed Effect on Jump Behavior in Forest Fires

Viegas, Domingos X.; Raposo, Jorge; Figueiredo, A.R.

doi:10.1016/j.proeng.2013.08.158

Cited by 16 publications

(28 citation statements)

References 3 publications

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“…When the fire passed into the fracture, its intensity and velocity were reduced, causing a lower impact on vegetation by reducing the contact and enhancing the height in relation to the soil. This event could be denominated as 'jump fire effect' ( Figure 5) when fire changes from the 'fuel bed' site to continue its route of passage (Viegas et al, 2013;Raposo et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Fire passage on geomorphic fractures in Cerrado: effect on vegetation

2017

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A fratura geomórfica é uma formação geológica natural, que em alguns casos forma uma fissura profunda na rocha, com o estabelecimento de solo e vegetação. O objetivo desse trabalho foi analisar a vegetação dentro das fraturas geomórficas sobre o efeito da passagem do fogo. Para isso, as seguintes variáveis biométricas foram avaliadas: diâmetro, altura, índice de área foliar, volume de madeira, biomassa herbácea, número de indivíduos e de espécies arbóreas e arbustivas, antes e depois da passagem do fogo. Esses dados foram comparados com as áreas adjacentes às fraturas (controle). O efeito da passagem do fogo sob a vegetação dentro da fratura geomórfica não foi significativa, pois o fogo seguiu a superfície do solo (cama de fogo formada pela biomassa das plantas) e quando encontrou com a fratura (mais úmida) mudou da superfície do solo para o dossel (pelo efeito de saltar do fogo), afetando não significativamente o número de indivíduos e espécies vegetais; então, a fratura poderia ser um refúgio para as plantas contra a passagem do fogo. Pode-se inferir em nosso modelo experimental de que a qualidade da cama de biomassa vegetal poderia ser mais importante do que a quantidade, e a variabilidade do microclima recruta as plantas para o refúgio (fratura geomórfica).

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Section: Discussionmentioning

confidence: 99%

Fire passage on geomorphic fractures in Cerrado: effect on vegetation

2017

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“…Although other studies did not propose a definition of EFB, the term EFB was used extensively to describe different forms of EFB. For instance, "can involve significant and rapid changes in fire behaviour without significant changes in ambient conditions" [29], "abrupt changes in fire behaviour characteristics" [30], "may induce very high values of the rate of spread" [31], etc.…”

Section: Introductionmentioning

confidence: 99%

Frequency of Dynamic Fire Behaviours in Australian Forest Environments

Filkov

Duff

Penman

2019

Fire

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Wildfires can result in significant social, environmental and economic losses. Fires in which dynamic fire behaviours (DFBs) occur contribute disproportionately to damage statistics. Little quantitative data on the frequency at which DFBs occur exists. To address this problem, we conducted a structured survey using staff from fire and land management agencies in Australia regarding their experiences with DFBs. Staff were asked which, if any, DFBs were observed within fires greater than 1000 ha from the period 2006–2016 that they had experience with. They were also asked about the nature of evidence to support these observations. One hundred thirteen fires were identified. Eighty of them had between one and seven DFBs with 73% (58 fires) having multiple types of DFBs. Most DFBs could commonly be identified through direct data, suggesting an empirical analysis of these phenomena should be possible. Spotting, crown fires and pyro-convective events were the most common DFBs (66%); when combined with eruptive fires and conflagrations, these DFBs comprise 89% of all cases with DFBs. Further research should be focused on these DFBs due to their high frequencies and the fact that quantitative data are likely to be available.

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“…In most cases, these consequences are a result of dynamic fire behaviours (Filkov et al 2018a(Filkov et al , 2018bTedim et al 2018;Viegas 2012). Although some have been described and investigated, there are others that require further study, such as fire coalescence and junction fires (or jump fires previously) (Hilton et al 2018;Raposo et al 2018;Thomas et al 2017;Viegas et al 2013;Viegas et al 2012). The convergence of separate individual fires into larger fires is known as coalescence and can lead to rapid increases in fire intensity and spread rate (Hilton et al 2017).…”

Section: Introductionmentioning

confidence: 99%

“…There is no clear answer what are the mechanisms that drive junction fires despite intensive investigation (Hilton et al 2018;Raposo et al 2018;Thomas et al 2017;Viegas et al 2013;Viegas et al 2012). Viegas et al (2012) started to study this phenomenon in the laboratory conducting numerous experiments.…”

Section: Introductionmentioning

confidence: 99%

Quantifying dynamic fire behaviour phenomena using Unmanned Aerial Vehicle technology

2019

El Sawah, S. (Ed.) MODSIM2019, 23rd International Congress on Modelling and Simulation.

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Catastrophic wildfires are often a result of dynamic fire behaviours. Although some of these behaviours have been described and investigated, others require further study. Fire coalescence and junction fires are particular cases of merging fire fronts and are common phenomena observed during bushfires. They are important as they can cause rapid escalation of fire behaviour and be dangerous for ground-based emergency personnel. There are a few studies devoted to investigation of merging fires in field conditions. There is a need for high temporal and spatial measurements of fire behaviour in field conditions in order to better understand this phenomenon and evaluate risks during bushfires and prescribed burning. The aim of this study was to test emerging technologies for better quantification of fire behaviour at field scales and evaluate their potential as an operational tool. Several small and medium scale field experiments were conducted during April 2019 on farmland in Victoria, Australia. Harvested wheat fields were used as experimental plots, as they form relatively homogeneous fuel beds. Fuel height varied from 18 to 40 cm with fuel load and moisture content at 1.1 t/ha and 11.9 % respectively. Wind speed varied in the range of 1.5-6.5 m/s. An Unmanned Aerial Vehicle (UAV) was used to capture high definition video imagery of fire propagation in synchronisation with sensor data from the onboard Global Positioning System (GPS) and Inertial Measurement Unit (IMU). These sensors enabled the platform/camera orientation and position in space to be aligned with the video footage of fire propagation and to be georeferenced in GIS software. Twenty-one junction fires and five inward parallel fire fronts (parts of the fire lines approaching each other) were identified during the experiments. The rate of spread (ROS) of merging fire fronts was found to be at least two times higher than for the basic fire fronts (the rate of spread of a linear fire front in the same fuel bed in no-slope conditions) and for junction fires with acute angles (< 14°) it increased 6 times and more. Inward parallel fire fronts spread much slower, varying between 0.05 and 0.25 m/s. Forty-six percent of junction fires had increase of the ROS at the final stage of the merging process in contrast to Thomas et al. (2017) and Viegas et al. (2012). Also, it was observed that the angle between two oblique fire fronts did not change significantly in time for the initial angles smaller than 34°. It can be assumed that the main fire front influences on the shape and ROS respectively of junction fires and laboratory experiments cannot fully replicate these conditions. Although the initial experimental conditions were very different in relation to scale, fuel and wind conditions, similar ROS to that shown in numerical simulations by Thomas et al. (2017) were observed in our field experiments. Further investigation is required to explain the similarities as the relationship between fuel load, wind speed and scale is not known. The comparison of corrected v...

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Preliminary Analysis of Slope and Fuel Bed Effect on Jump Behavior in Forest Fires

Cited by 16 publications

References 3 publications

Fire passage on geomorphic fractures in Cerrado: effect on vegetation

Fire passage on geomorphic fractures in Cerrado: effect on vegetation

Frequency of Dynamic Fire Behaviours in Australian Forest Environments

Quantifying dynamic fire behaviour phenomena using Unmanned Aerial Vehicle technology

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