Fire Behavior
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This study compared fire size, seasonality, and environmental conditions (e.g., wind speed, fuel moisture, biomass, vegetation type) of large human- and lighting-started fires that required a suppression response. Mean large fire size varied by three orders of magnitude: from 1 to 10 ha in the Northeast vs. >1000 ha in the West. Humans ignited four times as many large fires as lightning, and were the dominant source of large fires in the eastern and western U.S. (starting 92% and 65% of fires, respectively). Humans started 80,896 large fires in seasons when lightning-ignited fires were rare. Large human-started fires occurred in locations and months of significantly higher fuel moisture and wind speed than large lightning-started fires.
This mobile-friendly, current, and interactive map combines data from the National Digital Forecast Database and RAWS surface weather observations.
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This study seeks to examine the relationships between a set of NFDRS fire danger indices (Fire Danger Ratings, Staffing Level and the Ignition Component) and measures of fire activity (fire occurrence and final fire size) across the entire conterminous US over an 8-year period. We reveal that different regions of the US display different levels of correspondence between each of the fire danger indices and recorded fire activity. Areas in the Southern and Eastern Geographic Area Coordination Centers (GACCs) exhibit weaker correlations than those in the Northwest, Northern Rockies, Great Basin and Northern California GACCs. Peaks in fire occurrence are shown to occur at mid–low values of fire danger whereas final fire sizes increase monotonically with each fire danger index. Our findings appear to align with perceived shifts in management practices currently employed across the US and indicate that the ability of the NFDRS to apportion the resources required to combat large fires is in general well developed.
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This seminar was presented by Matt Reeves at the Missoula, MT, Rocky Mountain Research Station Fire Lab.
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This study found that cross-validated results generally indicate a higher occurrence of smaller fires when months preceding fire season are wet, while larger fires are more frequent when soils are dry. This is consistent with the concept of increased fuel accumulation under wet conditions in the pre-season. These results demonstrate the fundamental strength of the relationship between soil moisture and fire activity at long lead-times and are indicative of that relationship’s utility for the future development of national-scale predictive capability.
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The 2017 Fire Narrative and Timeline tells the story of successes and challenges, and also addresses emerging technology and science, such as Quantitative Risk Assessment, Risk Management Assistance Teams, and using Unmanned Aircraft Systems (drones) for infrared and reconnaissance flights.
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Large wildfire incidence has increased in forests throughout the western U.S. following changes in vegetation structure and pattern, along with a changing climate. Given this increase there is great interest in whether fuels treatments and previous wildfire can alter fire severity patterns in large wildfires. The 255,000 acre 2013 Rim Fire created an opportunity to study fuels treatment effects across a large forested landscape in the Sierra Nevada. We assessed the relative influence of previous fuels treatments (including wildfire), fire weather, vegetation and water balance on Rim Fire severity. We did this at three different spatial scales to investigate whether the influences on fire severity changed across scales.
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The World of Wildland Fire vision is to provide and connect fire science educators, trainers, and the public with scientifically solid and peer-reviewed teaching tools and techniques, using state-of-the-art materials, which will be free and accessible to all. This is done to significantly enhance the learning experience.
Visit Interagency Fuels Treatment Decision Support System (IFTDSS) website.
IFTDSS is a web-based software and data integration framework that organizes previously existing and newly developed fire and fuels software applications to make fuels treatment planning and analysis more efficient and effective. You must create an account to begin using this tool.
New 2021, compare weather impacts on fire behavior with IFTDSS.
Read more about IFTDSS update 3.1.1
Read more about Landscape Burn Probability capabilities added to IFTDSS in July 2019
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Much of the Murphy Wildland Fire Complex burned under extreme fuel and weather conditions that likely overshadowed livestock grazing as a factor influencing fire extent and fuel consumption in many areas where these fires burned. Differences and abrupt contrast lines in the level of fuels consumed were affected mostly by the plant communities that existed on a site before fire. A few abrupt contrasts in burn severity coincided with apparent differences in grazing patterns of livestock, observed as fence-line contrasts. Fire modeling revealed that grazing in grassland vegetation can reduce surface rate of spread and fire-line intensity to a greater extent than in shrubland types. Under extreme fire conditions (low fuel moisture, high temperatures, and gusty winds), grazing applied at moderate utilization levels has limited or negligible effects on fire behavior. However, when weather and fuel-moisture conditions are less extreme, grazing may reduce the rate of spread and intensity of fires allowing for patchy burns with low levels of fuel consumption.