Using the Coupled Atmosphere-Wildland Fire Environment modeling system
CAWFE
The Coupled Atmosphere-Wildland Fire Environment modeling system was used to produce the video below to show how it would predict the spread of the Camp Fire that burned through Paradise, California November 8, 2018.
This simulation of the first 8 hrs of the #CampFire was created using our CAWFE model (Coupled Atmosphere-Wildland Fire Environment).
The animation will help us understand the factors that made this #fire so deadly.#Paradise#CalFire
The CAWFE modeling system combines a numerical weather prediction (NWP) model that predicts how weather varies in time and space even in complex terrain with wildland fire behavior modules. These components are connected in two directions such that the evolving wind, along with fuel properties and terrain slope, directs where the fire grows and how fast, while heat released by the fire modifies its atmospheric environment thereby creating its own weather (e.g., fire-induced winds). The model is described in Clark et al. (2004) and Coen 2005a. Coen (2013) documents the model equations.
CAWFE was developed recognizing that fires interact with the atmosphere surrounding them and that this produces many fundamental fire behaviors. Research applying CAWFE showed that fire-atmosphere interactions produce numerous wildland fire phenomena, including the commonly-observed bowed shape (below); the heading, flanks, and backing regions; fire whirls; horizontal roll vortices.
The CAWFE was developed by Janice Coen and other scientists at the University Corporation for Atmospheric Research, as well as Don Latham (formerly USFS, Missoula), Francis Fujioka (formerly, USFS Riverside), Phil Riggan (USFS), and David Packham (Bureau of Meteorology in Australia).
The research will be supported by a $1.5 million award.
University of Maryland (UMD) Associate Professor Michael Gollner will co-lead a first-of-its-kind research effort to quantify the pulmonary and cardiovascular health consequences to firefighters exposed to wildland fire smoke. The research is supported by a $1.5 million award from the Assistance to Firefighters Grant Program administered through the Federal Emergency Management Agency (FEMA), a Department of Homeland Security agency.
The smoke of wildland fires—such as California’s Mendocino Complex of Fires, which burned 459,123 acres, destroyed 280 structures (including 157 residences), and killed a firefighter during the 2018 wildfire season—contains particulate matter, carbon monoxide, volatile organic carbon compounds, and other toxic hazards that could put firefighters at risk for chronic illnesses such as ischemic heart disease, cardiovascular disease, and chronic obstructive pulmonary disease (such as emphysema and chronic bronchitis).
Members of a hotshot crew work in smoke on the Cold Brook Prescribed Fire, October 23, 2014. Photo by Bill Gabbert.
But unlike structural firefighters who have relatively well-defined respiratory personal protective equipment standards for fighting fires in and near buildings, wildland firefighters have no standards or requirements for prescriptive respiratory protection. And because wildland firefighters are often deployed to a fire for weeks at a time with sometimes repeated deployments for several months over a summer, they experience an exposure pattern with unknown health risks.
“We put wildland firefighters in harm’s way to protect the natural environment, homes and property, and lives. The focus on firefighter safety has largely been about physical injuries such as burns—but as you can imagine, these firefighters are also exposed to a great deal of smoke,” explains Gollner, a fire protection engineer in UMD’s A. James Clark School of Engineering. “We know there can be health consequences to this, but we have no data on the long-term effect of wildland fire emissions on the heart, blood vessels, and lungs of front-line wildfire responders, because it’s incredibly difficult to study.”
The FEMA-funded research will look at different smoke exposures that mimic both smaller prescribed fires (i.e., planned fires that are used to meet management objectives and that consider the safety of the public, weather, and probability of meeting burn objectives) and larger wildfires—as well as the benefit provided by different types of simple respiratory personal protective equipment.
The research team, led by principal investigators and bioengineers Jessica Oakes and Chiara Bellini of Northeastern University, hopes the three-year project will inform which fire scenarios are the most dangerous with greatest risk to firefighters’ pulmonary and cardiovascular health. Perhaps most importantly, it could lead to recommendations for respiratory personal protective equipment that is easily implemented in the field and/or possible changes in tactics to mitigate exposure, with the goal of preserving firefighters’ long-term health.
“Unlike structural firefighters, who will put on an air-purifying respirator or a self-contained breathing apparatus when they enter a building, wildland firefighters typically cover their face with only a simple bandana,” says Gollner. “Bandanas are a common tactic because they don’t add an additional burden of weight to firefighters’ already strenuous activity. However, it is unknown if, or to what extent, this provides health benefits.”
The research team will combine their expertise to solve this challenging problem: Gollner will contribute novel expertise in firefighting practices and fire generation, while Oakes and Bellini will offer interdisciplinary bioengineering expertise that’s critical to understanding this complex health problem. They will also work with the International Association of Fire Fighters and National Fire Protection Association to facilitate input from stakeholder partners including firefighters from several departments across the country, fire organization representatives, health researchers, governmental agencies, and members of technical committees overseeing personal protective equipment standards.
Their instrument-laden C-130 conducted 16 research flights out of Boise
National Science Foundation C-130 used for studying wildfire smoke in 2018. NSF photo.
A C-130 outfitted with research equipment was based at Boise last summer in order to study smoke produced by wildfires. The missions were conducted by the National Center for Atmospheric Research which is a unit within the National Science Foundation. The name of the project is a mouthful: Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption and Nitrogen (WE-CAN) Field Campaign.
The organization provided this overview of the work they did over fires this year:
Western wildfire smoke has a significant impact on air quality, nutrient cycles, weather and climate. The chemistry inside a smoke plume during the first 24 hours after emission affects reactive nitrogen partitioning, cloud chemistry and nucleation, and aerosol scattering and absorption, all of which can impact air quality and climate.
The NSF-funded WE-CAN ground-based and airborne field campaign aimed to systematically characterize the emissions and first 24 hours of smoke plume evolution from western U.S. wildfires. The project, led by Dr. Emily Fischer at Colorado State University, focused on three science questions related to better quantifying processes associated with fixed nitrogen, absorbing aerosols, and cloud activation and chemistry in wildfire plumes. WE-CAN deployed a large suite of measurement instruments run by both university and NCAR teams on the NSF/NCAR C-130 and also involved a ground-based mobile component.
The C-130 was based in Boise, Idaho from 20 July – 31 August 2018 to maximize the opportunities to sample smoke plumes from northwestern wildfires in California, Oregon, Washington, Idaho, Montana, Utah, Nevada, and Colorado during the peak of the 2018 fire season. All three sampling goals of WE-CAN were achieved. In all, during the 16 research flights based out of Boise, 21 different wildfire plumes were sampled, each with a detailed fuel assessment provided by the local regional Fire Service. Following the research science portion of the field campaign, a subset of the instruments were run during an educational component, involving three flights based out of Broomfield, Colorado over a two-week period in early September 2018. During these flights, the C-130 sampled smoke plumes from two more fires, including a prescribed fire in Colorado.
Several ACOM teams deployed measurement instruments on the C-130 for WE-CAN, including the Trace Organic Gas Analyzer (TOGA; PI Eric Apel, Rebecca Hornbrook, Alan Hills), the HIAPER Airborne Radiation Package (HARP) actinic flux measurement (PI Sam Hall, Kirk Ullmann), the PAN Chemical Ionization Mass Spectrometer (PAN-CIMS; PI Frank Flocke), a Picarro CO-CO2-CH4 instrument and an Aerodyne Research Inc. CO-N2O-H2O instrument (PI Teresa Campos), and the NO-NO2-O3 (PI Andy Weinheimer, Denise Montzka, Geoff Tyndall). Preliminary data submissions for most data sets are due by 15 November 2018, and final quality controlled data are due 15 March 2019. Preliminary analyses will be presented by many teams at a targeted session at the 21st Conference on Atmospheric Chemistry at the AMS Annual Meeting in Phoenix, Arizona in January 2019.
Aerial view of the Rabbit Foot Fire in Idaho on 13 Aug 2018. Smoke from the Rabbit Foot Fire was sampled by the NSF/NCAR C-130 during three separate WE-CAN research flights and several times for longer durations by ground-based mobile labs. (Photo credit: Rebecca Hornbrook)
Researchers studying how wildfires have burned at a particular location found that subsequent fires have a “memory” that helped to self-regulate fire sizes and fire severity. When historical fires burned unabated, landscape patterns of surface and canopy fuels developed that provided barriers to future fire spread. Those same barriers can continue to influence the spread of additional fires.
Here are some additional highlights from their findings:
The Reburn Project was motivated by a need to better understand wildfires as fuel reduction treatments and to assess the impacts of decades of wildland fire suppression activities on forested landscapes. The study examined three areas, located in the inland Pacific Northwest, central Idaho and interior British Columbia. Each area had experienced a recent large wildfire event in montane forests.
Reburn Highlights
Past wildfires generally mitigate burn severity for a time, even under extreme fire weather conditions that are associated with large fires.
Since around 1900-1934, fire suppression and not wildfire has been a primary influence on forest and fuel succession. Quantifying the effects of fire suppression on particular landscapes is difficult given the long history and its prevalence across the region. Results from simulation modeling have the potential to illustrate in compelling ways the combined effects of removing fires from landscapes that experienced variable fire severity and spatial extent.
The researchers developed a state-transition model that allowed them to simulate the growth and potential severity 20th century ignitions that were suppressed. Fire growth simulations were modeled using the daily meteorology available at the time of the ignitions and the FSPro model. The researchers found that the simulated landscapes were reburn landscapes; i.e., the complexity of forest seral stage conditions and fuelbeds was an emergent property of successive reburning over the centuries, and fuel succession explained most of the severity patterns observed.
Modern-day fire suppression scenarios led to “boom and bust” landscapes, where continuous mature forests developed, that were capable of supporting large fire spread, and were eventually burned with mostly high severity. However, using a variety of historical landscape conditions as an initial basis, in scenarios where most or all fires were allowed to burn, fine- to meso-grained patchworks resulted, and they provided a highly diverse range of habitats and values over time, and landscapes were much less susceptible to large, high severity events. Instead, more typical fire size distributions and more characteristic variation in fire severity were restored.
A group of people knowledgeable about wildland fire have produced a 52-page document that attempts to assemble and summarize areas of agreement and disagreement regarding the management of forested areas in the western United States. Calling themselves the Fire Research Consensus Working Group, they looked for areas of common ground to provide insights for scientists and land managers with respect to recent controversies over the role of low-, moderate-, and high-severity fires.
Here is how they hope their conclusions will be used:
Our hope is that stakeholder groups will avoid the selective use of particular scientific papers to argue for their particular ends. Instead, they will be able to point to key shared assumptions, common understandings considering the entire body of fire science literature, and terminology to support decision-making in constructive ways. In particular, land and fire managers are a key audience for this report, as are other stakeholders and the interested public engaged in discussions about land management.
The “Executive Summary” is 6 pages long. Below is the section about high-severity fire:
“Respondents disagreed about whether large, high-severity fires have increased to a significant and measurable degree in all forest types in comparison to historical fire regimes (i.e., prior to modern fire suppression). There was strong agreement that in dry pine forests at low elevations there has been either an observed increase in high-severity fires or an increase in the potential for fires of elevated severity as the result of increased abundance and connectivity of woody fuels since the late 19th century. There was similar strong agreement about dry mixed-conifer forests in the Inland Northwest, Pacific Southwest, and Inland Southwest (Arizona and New Mexico) that there has been an increase in high-severity fires and an increase in the potential for fires of elevated severity. There was less agreement about the changes in extent, and causes of changes in extent, of high-severity fires in moist mixed-conifer forests. Although there is general agreement that high-severity fires historically played an important role in moist mixed-conifer and cold subalpine forests, there is strong disagreement over the degree of changes in burn severity patch-size distributions and associated successional conditions for these forests between different regions.
“Opinions also vary over the consequences of any increases in fire severity. For most dry forests, although there may be some disagreement about trends in burn severity and their causes, there is broad agreement that under current and projected climate, post-fire forest resilience is less than in the past. Some forest habitats, particularly at drier sites, but also in some moist and cold forest sites, show evidence of converting to more flammable non-forest vegetation or less dense forests following recent fires where large patches burn severely, especially if reburned. Reburn potential may depend on the interaction of vegetation, weather, rate of fire spread, time since prior fire, ignitions and fire suppression. Opinions are varied concerning the ecological consequences of departures from historical patterns of fire severity in various mixed conifer and subalpine forests. For example, one viewpoint supports the historical precedence of mixed-severity fire (including relatively large patches of high-severity fire), and the concept that pyrodiversity begets biodiversity. Another viewpoint asserts that increased woody fuel connectivity in combination with a warming climate trend is setting large areas of landscapes on fundamentally new trajectories, with significant undesirable ecological and societal consequences. Still a third viewpoint emphasizes that climatic changes increasingly are of overriding importance, and that new trajectories are unavoidable and thus may be considered desirable in many cases to incrementally foster necessary ecosystem transitions. The figure below characterizes these divergent viewpoints – typical of many areas of disagreement we addressed – and the potential common ground among them.
“Uncertainties associated with relative proportions of different burn severities and patch-size distributions combine to cloud key points of consensus that have important management implications. We suggest that resolving many fire science disagreements depends on greater consideration of specific geographical context. This may imply that a narrow range of field experience can limit one’s ability to accept findings that depart from that range. A logical way forward is to increase in-depth cross-regional field research experiences of the fire research community. Cross-regional comparisons of top-down and bottom-up determinants of fire activity in similar forest cover types is a fertile area of future research to examine how differences in seasonality, productivity, understory fuels, land use history, and other factors may explain some of the reported geographical differences in historical fire regimes in broadly similar forest types.
“There are several reasons for the disagreements about the amount and roles of past higher-severity fire. Both scientists and managers often transfer concepts and findings from one place to another, yet we know that “no one size fits all” for historical fire regimes, even within the same forest type. Likewise, the extent of change in abundance and connectivity of woody fuels varies across forest types and ecoregions. Some of the disagreement derives from use of different scientific approaches. For instance, there is strong debate about the fire regime inferences made from historical and modern tree inventory data, simulation models, and other approaches. We believe that application of diverse research approaches will be useful going forward. Further, multiple approaches will be useful in “triangulating” interpretations for which there is some scientific consensus (see Topic H). We challenge fire scientists who do not share similar perspectives on historical fire regimes in particular ecosystems to engage in civil discourse to better understand the reasons for their disagreement, and to objectively communicate those reasons to managers and other stakeholders. We are heartened by the positive outcomes achieved by some previous attempts when small or large groups work together to find common ground.”
Moritz, M.A., C. Topik, C.D. Allen, P.F. Hessburg, P. Morgan, D.C. Odion, T.T. Veblen, and I.M. McCullough. 2018. A Statement of Common Ground Regarding the Role of Wildfire in Forested Landscapes of the Western United States. Fire Research Consensus Working Group Final Report.
Thanks and a tip of the hat go out to Ben. Typos or errors, report them HERE.
Wildfire south of Porto, Portugal, September 2, 2012. Photo by Bill Gabbert.
The climate warming that we have been seeing is expected to continue along with the increased risk of larger, more suppression-resistant wildfires. Scientists have examined how this will affect fires in Europe up to a 1.5°C rise, which is the not-to-exceed target in the Paris climate agreement. Now a study is complete that examines increases of 1.5, 2, and 3°C warming scenarios. Not surprisingly, it found that the higher the warming level, the larger is the increase of burned area, ranging from ~40% to ~100% across the scenarios. Their results indicate that significant benefits would be obtained if warming were limited to well below 2 °C.
Ensemble mean burned area changes. Burned area changes (%) for a the +1.5 °C case with the stationary model SM (i.e., using Eq. 3), (b) the +1.5 °C case with non-stationary model NSM (i.e., NSM). using Eq. (4), (c) the +2 °C case with SM, (d) the +2 °C case with NSM, (e) the +3 °C case with SM, and f the +3 °C case with NSM. Dots indicate areas where at least 50% of the simulations (1000 bootstrap replications × the ensemble of RCMs) show a statistically significant change and more than 66% agree on the direction of the change. Coloured areas (without dots) indicate that changes are small compared to natural variations, and white regions (if any) indicate that no agreement between the simulations is found. Click to enlarge.
The paper, published in Nature, was written by Marco Turco, Juan José Rosa-Cánovas, Joaquín Bedia, Sonia Jerez, Juan Pedro Montávez, Maria Carmen Llasat, and Antonello Provenzale.
