The effect of aerial suppression on the containment time of Australian wildfires estimated by fire management personnel

2012 ◽  
Vol 21 (3) ◽  
pp. 219 ◽  
Author(s):  
M. P. Plucinski ◽  
G. J. McCarthy ◽  
J. J. Hollis ◽  
J. S. Gould

The addition of aerial firefighting resources to wildfire suppression operations does not always result in faster fire containment. In this paper, containment times of fires with aerial suppression are compared with estimated containment times for the same fires without aerial suppression. Senior firefighting personnel who had worked on each fire estimated whether fires could have been contained within a time class if aircraft were not available. Data from 251 wildfires were analysed based on four fire-containment time classes: ≤2, 2–4, 4–8 and 8–24 h from the start of initial attack. Aircraft were perceived to reduce time to containment when firefighting conditions were more challenging owing to fuel hazard rating, weather conditions, slope, resource response times and area burning at initial attack. Comparisons of containment time with and without aircraft can be used to develop operational tools to help dispatchers decide when aircraft should be deployed to newly detected fires.


2006 ◽  
Vol 36 (12) ◽  
pp. 3155-3166 ◽  
Author(s):  
M Cecilia Arienti ◽  
Steven G Cumming ◽  
Stan Boutin

Canadian fire managers seek to contain fires below some target size (here 3 ha) by initial attack (IA). Suppression failures occur when fire size at IA exceeds this target (a response failure) or if an initially small fire cannot be contained below it (a containment failure). We examined the effects of cause, season, forest fuels, anthropogenic linear features, weather, and fire management (response time, size at IA) on the probability of these two types of suppression failures, using multiple logistic regression on 1196 fires that occurred within the boreal mixedwood forest of northeastern Alberta during 1995–2002. The frequencies of containment (7%) and response failures (10%) were similar, but the latter accounted for 85% of the area burned. Response failure probability was greater for fires caused by lightning than those caused by humans and increased with longer response times, local abundance of black spruce in summer, and pine fuel under severe fire weather. We found no effect of linear features or other fuel types. Containment failure probability was related to size at IA and fire weather conditions. Our models suggest that a reduction in area burned might be possible if additional fire-specific factors affecting response failure probability could be incorporated into operational decisions.



2013 ◽  
Vol 43 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Yohan Lee ◽  
Jeremy S. Fried ◽  
Heidi J. Albers ◽  
Robert G. Haight

We combine a scenario-based, standard-response optimization model with stochastic simulation to improve the efficiency of resource deployment for initial attack on wildland fires in three planning units in California. The optimization model minimizes the expected number of fires that do not receive a standard response — defined as the number of resources by type that must arrive at the fire within a specified time limit — subject to budget and station capacity constraints and uncertainty about the daily number and location of fires. We use the California Fire Economics Simulator to predict the number of fires not contained within initial attack modeling limits. Compared with the current deployment, the deployment obtained with optimization shifts resources from the planning unit with highest fire load to the planning unit with the highest standard response requirements but leaves simulated containment success unchanged. This result suggests that, under the current budget and capacity constraints, a range of deployments may perform equally well in terms of fire containment. Resource deployments that result from relaxing constraints on station capacity achieve greater containment success by encouraging consolidation of resources into stations with high dispatch frequency, thus increasing the probability of resource availability on high fire count days.



2019 ◽  
Vol 666 ◽  
pp. 915-927 ◽  
Author(s):  
Marcos Rodrigues ◽  
Fermín Alcasena ◽  
Cristina Vega-García


2004 ◽  
Vol 34 (3) ◽  
pp. 705-715 ◽  
Author(s):  
Kelvin G Hirsch ◽  
Justin J Podur ◽  
Robert F Janser ◽  
Robert S McAlpine ◽  
David L Martell

A structured expert-judgement elicitation technique was used to develop probability distributions for fireline production rates for Ontario's three- and four-person initial-attack crews for seven common fuel types and two distinct levels of fire intensity (i.e., low, 500 kW/m; moderate, 1500 kW/m). A total of 141 crew leaders provided 900 estimates of the minimum, maximum, and most likely (mode) time to construct 610 m (2000 ft) of fireline. This information was used to estimate parameters for beta probability distributions for each individual and scenario. Analysis of variance (ANOVA) of the beta-distribution parameters (α and β) and the three time estimates indicated that fuel type, intensity, crew size, and crew-leader experience all have a statistically significant (p < 0.05) influence on estimated crew productivity. The 28 scenario-specific and 7 aggregated distributions and expected values can be used in many operational fire-management activities (e.g., presuppression planning, initial-attack dispatching, initial-fire assessments) and incorporated into initial-attack containment models. These results also provide baseline data on crew productivity that can be used in larger strategic analyses to gauge the benefits of new fire-suppression equipment and techniques for the entire fire-management program.



AmS-Skrifter ◽  
2021 ◽  
pp. 1-131
Author(s):  
Lotte Selsing

The geographical and altitudinal distribution of the data from 68 palynological sites has allowed the synthesis of a relationship between the microscopic charcoal curves and people over time. Most of the selected sites were of archaeological interest. Quantitative methods, qualitative methods and topics about the relation between fire, charcoal, nature and people in a forested landscape were used. Palynological sites are better suited to revealing fire management activities in the Mesolithic than archaeological sites because intentional burning of vegetation was carried out in areas related to lakes and mires. Climate is ruled out as the cause of the charcoal occurrence because there are no correlations between inferred regional climatic changes and the charcoal. This suggests that an anthropogenic explanation for the charcoal occurrence is the most plausible.There are many indications that hunter-gatherers in the Mesolithic used fire management and that fire was an important part of cultural practice associated with settlement, population density and resource needs. Fire management was a common and regular work task integrated with other activities. The traditional lifestyle of foragers may have included customary controlled burning practices as a part of manipulating the ecological succession and the modification of vegetation communities. Burning may have been central to hunting and gathering practices and the key to many social and cultural activities. The timing of burns may have been related to weather conditions, time of year and annual cultural events.The different pattern of temporal changes in charcoal abundance suggests that no widespread burning (i.e. on a regional or landscape-scale) had taken place. The anthropogenic burning was different from natural fires. The fires set by people were smaller and less intense. Selected areas of vegetation were burnt on a recurrent basis. They were predictable, almost immediately productive, creating mosaics in a complex pattern of vegetation of burnt and unburnt patches. Because they reduced available fuel, they provided protection against the disruptions of natural fires. The occurrence of natural fires is irregular, often with long intervals in between; they are uncontrolled, unpredictable, destructive to the vegetation and potentially dangerous for people. In order for the recorded charcoal occurrences to be considered the result of natural fires, sites close to each other should have had similar charcoal occurrences, but this is not the case. An often low and continuous charcoal presence in a more or less dense forest in the Mesolithic indicates a continuous production of charcoal, which is better interpreted as people’s use of fire than continuous natural fires. The data confirm that anthropogenic fires were much more frequent than natural fires in the Mesolithic. Foragers did not simply adjust to their environment, but had an active, dynamic relationship with nature, using intentional burning both to modify and to maintain the environment. Intentional burning of vegetation during the Mesolithic is suggested to have been enacted by foragers who controlled fire for many purposes and widened its application to preserve their basis of existence, for instance to improve the outcome of hunting and for communication. Two periods with a high frequency of maximum values of charcoal in the pollen diagrams are recorded in the early (9800–6000 cal yr BP) and the late part of the Holocene (younger than 2400 cal yr BP), respectively, and not at the transition to the Neolithic. This shows that early farmers did not produce as much charcoal—measured in maxima—as the huntergatherers did before the transition to the Neolithic, and confirms foragers’ intentional burning as part of Mesolithic land-use in South Norway. The first occurrences and high frequency of maximum values of charcoal pre-date the transition to the Neolithic and thus it can be ruled out that they were correlated with agrarian cultures in South Norway. It is possible that the selective burning carried out by foragers in vegetation paved the way for pioneer farmers to convert land for agricultural purposes. In that sense, the neolithisation was not very revolutionary, as the knowledge of using fire to manipulate and open the forest had a long pre-agrarian history. As the path of the charcoal curve following the transition to the Neolithic is often interpreted as the result of forest clearance by farmers, a fire-related woodland change interpretation for the Mesolithic might also be used. After the transition to the Neolithic, the density of the forest in many areas decreased and allowed more charcoal deposition. The density of the forest affected the charcoal curve resulting in low values before the transition to theNeolithic compared to the values after the transition. This is a strong indication that the charcoal curve during the Mesolithic mainly originated as an effect of human activities. That the density of the forest in the Mesolithic changed more than the traditionally accepted view is probably the result of intentional fire management. 



2013 ◽  
Vol 1 (5) ◽  
pp. 4539-4564
Author(s):  
O. F. Price ◽  
R. A. Bradstock

Abstract. In order to quantify the risks from fire at the Wildland Urban Interface (WUI), it is important to understand where fires occur and their likelihood of spreading to the WUI. For each of 999 fires in the Sydney region we calculated the distance between the ignition and the WUI, the fire weather and wind direction and whether it spread to the WUI. The likelihood of burning the WUI was analysed using binomial regression. Weather and distance interacted such that under mild weather conditions, the model predicted only a 5% chance that a fire starting more than 2.5 km from the interface would reach it, whereas when the conditions are extreme the predicted chance remained above 30% even at distances further than 10 km. Fires were more likely to spread to the WUI if the wind was from the west and in the western side of the region. We examined whether the management responses to wildfires are commensurate with risk by comparing the distribution of distance to the WUI of wildfires with roads and prescribed fires. Prescribed fires and roads were concentrated nearer to the WUI than wildfires as a whole, but further away than wildfires that burnt the WUI under extreme weather conditions (high risk fires). 79% of these high risk fires started within 2 km of the WUI, so there is some argument for concentrating more management effort near the WUI. By substituting climate change scenario weather into the statistical model, we predicted a small increase in the risk of fires spreading to the WUI, but the increase will be greater under extreme weather. This approach has a variety of uses, including mapping fire risk and improving the ability to match fire management responses to the threat from each fire. They also provide a baseline from which a cost-benefit analysis of complementary fire management strategies can be conducted.



2013 ◽  
Vol 22 (4) ◽  
pp. 459 ◽  
Author(s):  
Matt P. Plucinski

Most grassfires that occur in southern Australia are contained to small areas by local suppression resources. Those that are not require extra resources from neighbouring districts. Identifying these fires at the start of initial attack can prompt early resource requests so that resources arrive earlier when they can more effectively assist with containment. This study uses operational data collected from Australian grassfires that used ground tankers and aircraft for suppression. Variables were limited to those available when the first situation report is provided to incident controllers and included weather parameters, resource response times, slope, curing state, pasture condition and estimated fire area at initial attack. Logistic regression and classification trees were used to identify grassfires likely to escape initial attack by (a) becoming large (final area ≥100 ha), (b) being of long duration (containment time ≥4 h) or (c) either or both of these. These fires would benefit from having more resources deployed to them than are normally available. The best models used initial fire area and Grassland Fire Danger Index as predictor variables. Preliminary operational decision guides developed from classification trees could be used by fire managers to make quick assessments of the need for extra resources at early stages of a fire.



1996 ◽  
Vol 6 (4) ◽  
pp. 199 ◽  
Author(s):  
KG Hirsch ◽  
DL Martell

Information regarding the productivity and effectiveness of initial attack fire crews is essential to a wide variety of forest fire management activities. This paper provides a selective review of crew productivity research conducted in Australia, Canada, and the United States and a cursory overview of how such information is used in computer-based fire management decision support systems. A description of several widely used rules-of-thumb that relate suppression effectiveness to fire intensity is presented as well as our understanding of how these guidelines may have evolved. This is followed by an example of some of the difficulties associated with transferring productivity and effectiveness information between fire management organizations and fire environments. The paper concludes with a discussion of strategies for investigating initial attack crew performance.



2019 ◽  
Vol 28 (1) ◽  
pp. 15 ◽  
Author(s):  
Ambika Paudel ◽  
David L. Martell ◽  
Douglas G. Woolford

The success of forest fire initial attack systems is believed to be affected by many factors including the initial attack response time. Despite the fact that fire managers typically strive to dispatch initial attack resources to most fires soon after they are reported in order to minimise their response time, they may not always be able to do so as the timing of the initial attack dispatch can be influenced by many factors. We examine the effects of the following factors on the initial attack dispatch process: the daily fire load (the number of fires reported each day), the time of day the fire was reported, fire weather conditions, fire cause and the month of the fire season, on the probability that initial attack resources are dispatched on the day that a fire is reported. Logistic regression methods are used to analyse a dataset composed of 4532 forest fires that were reported in our study area in a portion of northeastern region of Ontario, Canada, during 1963–2012 fire seasons. Our results indicate that the time of day a fire is reported, the total number of fires reported on that day and the Initial Spread Index are key factors that influence the timing of the initial attack response in our study area.



1989 ◽  
Vol 19 (8) ◽  
pp. 997-1003 ◽  
Author(s):  
David H. Anderson

The problem of containment of wildland fires is considered. One method of attack is to attempt to put out the flames directly. This involves the suppression team working at the fire front during the entire containment process. This method is not possible if the fire is spreading too rapidly. The analysis presented in this paper outlines conditions under which containment using such a direct method is possible. A less restrictive alternative is to use some method of indirect attack. A method is presented that would be simple to apply in practice, and even if the method itself is not used, it would assist fire managers in preliminary fire control planning and initial attack dispatching. Estimates are required for various parameters controlling the spread of the free-burning fire, and these can either be obtained directly from the user or from a fire-modelling computer program such as the USDA Forest Service BEHAVE program.



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