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Management notes Volume 59 * No. 2 * Spring 1999 Contents On the Cower: Y2K—Why Me?. 4 Mike Funston, Mike Barrowcliff, and Bill Rush Classification of Fire Simulation Systems. 5 Dorothy Albright and Bernard N. Meisner FARSITE—A Program for Fire Growth Simulation. 13 Mark A. Finney and Patricia L. Andrews BEHAVE Fire Modeling System: Redesign (A) The Hell Roaring Fire, a and Expansion. 16 crown Fire in lodgepole pine, Patricia L. Andrews and Collin D. Bevins Yellowstone National Park, WY, 1988. (B) Computer equipment NEXUS: A System for Assessing Crown in a Fire camp, Yellowstone Fire Hazard. 20 National Park, WY August Joe H. Scott 1988. Information systems play a vital role in all aspects A Wildfire Threat Rating System. 25 of wildlarid Fire management today. Photos: Tiana Glenn, Brad Hawkes and Judi Beck USDI Bureau of Land Manage¬ ment, National Interagency A Fire-Based Hazard/Risk Assessment. 31 Fire Center, Boise, ID, 1988. Timothy A. Burton, Deirdre M. Dether, John R. Erickson, Joseph P. Frost, Lynette Z. Morelan, Leon F. Neuenschwander, William R. Rush, John L. Thornton, and Cydney A. Weiland Sharing Information Through Fire Reporting. 37 Delvin R. Bunton New Weather Observation Transfer Format. 43 The FIRE 21 symbol (shown below and on the Delvin R. Bunton cover) stands for the safe and effective use of wildland fire, now and in the 21st century. Its shape represents the Fire triangle (oxygen, heat, Systems Help Desk Serves the Wildland and fuel). The three outer red triangles represent the basic functions of wildland Fire organi¬ Fire Community. 45 zations (planning, operations, and aviation Suz Rittenhouse management), and the three critical aspects of wildland Fire management (prevention, suppression, and prescription). The black interior represents land affected by Fire; the Short Features emerging green points symbolize the growth, restoration, and sustainability associated with Fire-adapted ecosystems. The flame represents Don’t Get Bitten by the Millennium Bug!. 30 Fire itself as an ever-present force in nature. For Delvin R. Bunton more information on FIRE 21 and the science, research, and innovative thinking behind it, contact Mike Apicello, National Interagency Fire Business Continuity Planning for January 1, 2000 . .. 47 Center, 208-387-5460. Delvin R. Bunton Websites on Fire. 47 Guidelines for Contributors Inside front cover Firefighter and public safety is our first priority Y2K—Why Me? Mike Funston, Mike Barrowcliff, and Bill Rush s the new millennium ap¬ We are working to ensure that, proaches, many wildland fire managers want to know what by the end of February 1999, (if any) problems they might en¬ ali critical applications are Y2K compliant counter with the computer appli¬ and migrated off the Data General. cations they use after January 1, 2000. Almost everyone has heard that many computer applications initiate repairs, and verify the Meeting these two objectives is were originally written to process results. This sounds easy, but we NIST’s main focus. dates with years that have only two found that many of the date-code digits. This works fine in process¬ issues were very subtle and some¬ We are heavily engaged in migra¬ ing information from a single times required much more effort tion efforts and Y2K fixes, and will century, but it won’t work for to detect and repair than originally be very busy during winter 1999 information that spans the anticipated. Moreover, this is one meeting our objectives. The millennia. project for which the deadline functionalities of some applica¬ Origins of the Problem (January 1, 2000) is absolutely tions are being consolidated into a fixed and cannot be changed. single replacement application. Some might wonder why com¬ Other applications will undergo puter programmers were so Finding a Solution significant “facelifts.” Still others shortsighted as to create a ticking will change in stages as they In the Forest Service, efforts were time bomb. The main reason is gradually evolve on the new already under way to migrate our that way back in the “Dark Ages,” platform(s). existing computer applications computer programmers had to from the Data General to the new devise clever ways to conserve All this is necessary to ensure that IBM platform. Migration coincided precious memory and disk space, a there is no disruption to the with our Year 2000 (Y2K) renova¬ concern that advancing computer operation of critical applications tion efforts, providing us with an technology has virtually elimi¬ after January 1, 2000. We ask the opportunity to address both issues nated. Whatever the reason, the indulgence of the wildland fire simultaneously. Accordingly, we problem is real and requires community during this potentially implemented a strategy to ensure prompt attention. difficult period of transition, and that, by the end of February 1999, we thank everyone for their all critical applications were: In October 1997, the USDA Forest continued patience. Service’s National Fire and Avia¬ • Certified for Y2K compliance, tion Information Systems Team and (NIST) began a concerted effort to • Migrated off the Data General. assess the applications in question, Mike Funston is the branch chief for the USDA Forest Service's National Fire and Aviation Information Systems Team (NIST), Washington Office, Washington, DC; and Mike Barrowcliff and Bill Rush are section heads for NIST, National Interagency Fire Center, Boise, ID. Fire Management Notes Classification of Fire Simulation Systems* WDorothy Albright and Bernard N. Meisner ith the advent of powerful Capable of accurately predicting fire behavior, computer workstations, a growing number of fire fire simulation systems can be valuable tools simulation systems are emerging for today’s wildland fire managers. for use by wildland fire planners and managers. These systems, with their graphical user interfaces, and decide which ones best meet Physical-Statistical. Physical- linkages to digital maps produced their needs. statistical fire prediction models by geographic information systems combine physical theory with (GIS’s), and colorful outputs of Fire Prediction Models statistical correlation to generate spatial fire patterns, have taken formulas for fire behavior. Ex¬ wildland fire prediction beyond As components of fire simulation amples include: tables and graphs to three-dimen¬ systems, fire prediction models sional displays of fire behavior simulate fire behavior (such as rate • RothermeVs (1972) model as across entire landscapes. Capable of spread, fire intensity, and flame incorporated into the BEHAVE of consistently representing fire height) using site-specific data Fire Behavior Prediction and such as weather, terrain, and fuel behavior and spatially validating Fuel Modeling System (Andrews type and condition. A spreading fire prediction models, today's fire 1986). Based on the principle of simulation systems can be valuable fire releases energy from combus¬ conservation of energy, tools for wildland fire manage¬ tion and transports some of it to Rothermel (1972) represents the ment. adjacent unburned fuels, heating rate of fire spread as a function them to the point of ignition of fuel density, particle size, bulk A fire simulation system combines (Albini 1985). Different fire predic¬ density, and rate of fuel con¬ an underlying fire prediction tion models use different predic¬ sumption. Because an analytical model with a fire simulation tive methods to quantify these fire solution to the problem of fire technique. By categorizing the spread processes. There are four behavior is not possible on this various types of fire prediction different types of fire prediction basis, Rothermel approximates a models and simulation techniques, models: physical, physical-statisti¬ solution from laboratory we can identify the similarities and cal, statistical, and probabilistic. experiments. differences among the systems. • The Canadian Forest Fire The resulting classification scheme Physical. Physical fire prediction Behavior Prediction (FBP) for fire simulation systems can models predict fire spread based on System (Forestry Canada Fire enable fire managers and planners the physics of combustion. They Danger Group 1992). Based on distinguish among three modes of to compare the various systems moisture physics research and heat transfer: conduction, convec¬ heat transfer theory, the FBP tion, and radiation. For example, Dorothy Albright is a resource informa¬ System uses observations from tion specialist for the USDA Forest Service, Albini (1986) models fire spread by Fire and Aviation Management, Mather, balancing two-dimensional radia¬ 495 experimental fires and CA; and Bernard Meisner is the assistant wildfires to relate fuel character¬ tive heating against the cooling chief of the Scientific Services Division, istics to features of fire behavior U.S. Department of Commerce, National countereffect of reradiation and Weather Service, Southern Region, Fort convection on unignited fuels. such as rate of spread and fuel Worth, TX. consumption. Although several physical models have been developed, none are *This article summarizes a more detailed treatment of this subject by the authors. For a copy of the full currently used in fire management Statistical. Statistical fire predic¬ paper, contact Dorothy Albright, USDA Forest Service, tion models fit a set of equations to Fire and Aviation Management, 3735 Neely Way, because they require such large Mather, CA 95655, tel. 916-364-2823, fax 916-364-2820. amounts of detailed data. data derived from test fires. The Volume 59 • No 2 • Spring 1999 5 equations predict fire parameters Given sufficient resolution, such as rate of spread, fuel con¬ fire simulation systems can describe sumption, and fireline intensity. fire behavior in heterogeneous fuels Because these models are not based on physical processes, their over varied terrain. success in predicting fire behavior is limited to conditions similar to those of the test fires. For example, as a lattice of discrete boxes or nique represents the landscape as a McArthur’s fire danger meters elements, then the spread of fire lattice of boxes or cells, each with a (McArthur 1966; Noble et al. 1980) from one box to the next is gov¬ set of possible values (such as describe forest and grassland fire erned by a specific set of rules or a slope, aspect, fuel type, or fuel behavior based on more than 800 probability of occurrence. If the condition). Each cell begins in an fires, but do not consider the landscape is shown as a continuous initial state at the time of ignition. physical relationship between medium, the shape of the fireline The likelihood of fire spreading to parameters. is represented by mathematical each cell in the lattice is deter¬ functions. mined by a set of rules that are the Probabilistic. Probabilistic fire same for all cells. These rules prediction models are based on Bond Percolation. The bond relate the future state of the cell to contingency tables rather than percolation fire simulation tech¬ its initial state and the states of the physical or statistical equations. In nique represents the landscape as a neighboring cells. Users can use probabilistic models, each environ¬ lattice of square, triangular, or parameters such as fuel type and mental variable (such as fuel type, hexagonal boxes. A fire in one box moisture, topography, and weather fuel moisture, and windspeed) is spreads to neighboring boxes that to determine the spread of fire assigned to one of several discrete contain ignitable fuel. Users can through the lattice. Because the categories. The probabilities in the adjust spread probability for rules relating fire spread among contingency tables are then used direction of spread due to factors the lattice of cells can be based on to simulate the likely fire spread such as wind velocity, topography, physical processes, the cellular from one location to the next. and differences in fuel types automaton technique can apply to Because the numerical values for (MacKay and Jan 1984; Ohtsuki a wide variety of conditions. the probabilities are not based on and Keyes 1986). If most of the physical processes, probabilistic boxes contain unburned fuel and The attractiveness of using the models are applicable only under the probability of propagation is bond percolation and cellular conditions similar to those for high, then the fire spreads (perco¬ automaton techniques to simulate which they were developed. They lates) throughout the lattice. fire spread lies in the fundamental are usually used to simulate the simplicity of their components for ignition and probability of spread A bond percolation technique must producing an overall fire behavior for a sequence of hypothetical fires be “tuned” by adjusting the prob¬ that can be extremely complex over a landscape, not for predicting abilities such that the modeled fire (Wolfram 1984). Both techniques the rate of spread for a specific fire. spreads in a manner comparable to yield reasonable estimates of fire that of actual fires over similar spread when its physical determi¬ Fire Simulation terrain under similar weather and nants are unknown. Techniques fuel conditions. Because the technique is not based on a physi¬ Elliptical Wave Propagation. The Every fire simulation system uses, cal process, success in simulating elliptical wave propagation fire in addition to an underlying fire fire spread is limited to conditions simulation technique projects the prediction model, a fire simulation similar to those for which the landscape as a continuous medium technique to represent the spread technique has been tuned. rather than as a lattice of boxes or of fire through the landscape. Fire cells. Fires burning in continuous simulation techniques differ from Cellular Automaton. Like the bond uniform fuels under constant each other in how they represent percolation technique, the cellular conditions of slope, wind velocity, the landscape and the spreading automaton fire simulation tech¬ and fuel moisture assume an process. If the landscape is shown 6 Fire Management Notes Fire simulation systems should be capable Most fire prediction models depend on a quantitative description of of meeting different requirements, including forest fuels in terms of a set of wildfire suppression, prescribed burning, fire standard or custom fuel models, or management training, and public education. on empirical data from a particular landscape. For example: elliptical shape (Richards 1990). Additional • Models based on Rothermel Based on Huygens principle of Considerations (1972) such as BEHAVE require wave propagation, Anderson et al. inputs based on the standard fire In choosing a fire simulation (1982) identify regularly spaced behavior fuel models (Anderson system, fire planners and managers points on the fire perimeter where 1982) developed to characterize should consider other factors in small fires spread elliptically typical surface fuels. Parameters addition to modeling and simula¬ outward, with the size and shape of include fuel loading, surface- tion techniques, such as intended each ellipse determined by local area-to-volume ratio, fuel depth, use, required inputs, associated conditions. The fire perimeter at fuel particle density, heat con¬ outputs, and required platform and each succeeding time step is the tent of fuel, and moisture of software. envelope that encompasses all of extinction (the minimum fuel the small ellipses burned. moisture content that begins to Intended Use. The developer of a affect fire spread). fire simulation system usually For this group of ellipses, Richards • The FBP System (Forestry describes its intended use. How¬ (1990) develops a set of differential Canada Fire Danger Group 1992) ever, prospective users can also equations that describe fire spread requires inputs based on 16 deduce the intended use from the for variable fuel, weather, and discrete fuel types in 5 major fuel underlying fire prediction model. topographic conditions. The size groups (coniferous, deciduous, For example: and shape of each ellipse depends mixed wood, slash, and open). on a small set of parameters based Parameter values derived from • BEHAVE is designed to describe on the FBP System (Forestry empirical data for rate of spread an advancing flame front in Canada Fire Danger Group 1992). are given for each fuel type. surface fuels less than 6 feet Although the technique does (1.8 m) from the ground require some numerical adjust¬ Additional required inputs depend (Rothermel 1983); ments to ensure that the small on the system’s fire prediction • The FBP System is intended to fires do not overlap or burn model. For example: describe fire behavior for specific previously burnt areas and that the fuel types: and simulated ignition points on the • Systems using the empirical • The probabilistic models are perimeter remain evenly spaced, a Rothermel model require data on designed to describe potential user can implement a finite dead fuel moisture content, live burn patterns on a landscape difference solution to the equa¬ fuel moisture content, slope, and scale. tions on a PC. wind direction and speed. • Models based on the FBP System Inputs. Fire simulation systems The elliptical wave technique require additional inputs such as require two general types of input: requires no local tuning, assuming weather, topography, and foliar that the fuels, weather, and topog¬ moisture content. 1. Digital maps (such as GIS’s) raphy in the area of interest are showing the spatial distribution sufficiently similar to those for Outputs. The outputs generated by of topography, fuel type and which the underlying parameters the different fire simulation condition, and weather; and were recorded. However, this systems vary in complexity. All 2. Descriptive numerical technique should not be used systems generate maps of predicted parameters. under conditions for which repre¬ fire perimeters over the study area. sentative parameters are not Some offer additional output available. Volume 59 • No 2 • Spring 1 999 options, such as graphs and charts Sample Fire Simulation automaton. The system can also showing fire area, intensity, spread Systems simulate fire behavior for a single rates, and other data. Output fire under varying or constant Table 1 compares recently de¬ resolution generally depends on conditions (Clarke 1994). veloped fire simulation systems. input resolution. Each system is described below. Input data are obtained from Platform and Software. Most fire remote sensing, U.S. Geological Clarke Cellular Automation Sys¬ simulation systems run on PC’s or Survey digital elevation models tem. The fire simulation system UNIX workstations. None require a (DEM's), and local environmental developed by Clarke et al. (1993) Macintosh platform and software, conditions. The input includes GIS uses simulations of potential but some require additional maps of fuel types and terrain. wildfire propagation and extinction software such as a GIS package Additional input includes tempera¬ behavior to assess fire risk. One (e.g., pMAP or ARC/INFO), and ture, relative humidity, fuel version of the system uses a others might require program¬ moisture, and a table of wind probabilistic approach to estimate ming language compilers such as direction and speed. Other factors fire risk based on a Monte Carlo C or FORTRAN. are calibrated using site data such implementation of the cellular Table 1—Comparison of numerical fire simulation systems Components Input Fire simulation Prediction Simulation Platform and system model technique Intended use CIS Additional Output software Clarke Cellular Probabilistic Cellular To simulate land- • Vegetation • Temperature Map of fire risk UNIX workstation Automation System automaton scape-scale fire • Elevation • Relative humidity (98-foot (30-m) with C compiler and (Clarke et al. 1993) risk and assess¬ • Fuel moisture • Windspeed resolution) Xwindows interface ment as well as • Wind direction burn patterns. DYNAFIRE Physical-statistical Cellular To simulate the • Standard fuel • Temperature Maps of: PC with MS-DOS (Kalabokidis et al. (BEHAVE) automaton spread of low- to types • Relative humidity • Fire perimeter and pMAP 1991; Hay 1991) moderate-intensity • Elevation • Fuel moisture • Fireline intensity surface fires. • Slope • Windspeed • Average spread • Aspect • Wind direction rate • Stream network EMBYR Probabilistic Bond percolation To simulate land¬ • Vegetation clas¬ • Fuel moisture Map of final burn UNIX workstation (Hargrove et al. scape-scale burn sified by species • Windspeed pattern (164-foot with FORTRAN 1995) patterns. and age • Wind direction (50-m) resolution) compiler FARSITE Physical-statistical Elliptical wave To simulate the • Standard/custom • Temperature Maps of: PC with Windows 3.1 (Finney 1993) (BEHAVE) propagation spread and behavior fuel types • Relative humidity • Fire behavior and WIN32S, of wildland fire. • Elevation • Windspeed • Fire perimeters Windows NT. or • Slope • Wind direction (adjustable Windows 95 • Aspect • Canopy resolution) • Canopy cover characteristics FIREMAP Physical-statistical Cellular automaton To simulate the • Standard fuel • Temperature Maps of: UNIX workstation (Ball and Guertin (BEHAVE) spread of low- to types • Relative humidity • Spread rate with PROMAP 1992) moderate-intensity • Elevation • Fuel moisture • Fireline intensity surface fires. • Slope (optional) • Flame length • Aspect • Windspeed • Heat/unit area • Wind direction • Reaction intensity • Fire perimeter WILDFIRE Physical-statistical Elliptical wave To simulate the • Standard fuel • Windspeed Maps of: PC with MS-DOS (Wallace 1993) (FBP System) propagation spread of low- to types • Wind direction • Fire perimeters moderate-intensity • Elevation • Fire intensity surface fires. (3.3-foot (1-m) resolution) 8 Fire Management Notes