Evaluating Expected Fire Behavior
- What Makes a Good Analyst
- Selecting the Best Tool
- Basic Fire Behavior Tools
- Spatial Analysis Tools
- Online Resources
What Makes a Good Analyst (Mark Finney...FBSC YouTube Video)
Selecting the Best Tool
The fire spread and intensity models have been configured in a variety of forms to address fire potential in different temporal and spatial configurations. This table can help focus the assessment with the most helpful information.
|How will the tool help answer your question?
How will fire behavior change with the next big change in fire environment?
Where will fire go today and how long will it take?
How will fire behavior vary across areas of interest during the burn period?
|Where will fire go over several days given changing weather as well as fuel and terrain?
|What risk do identified values face over a given planning period?
|Tool or Model
|Short-Term Fire Behavior (STFB) or FlamMap Minimum Travel Time (MTT) (Finney 2002).
|Near-Term Fire Behavior (NTFB) or FARSITE (Finney 1998).
|Best Use, Calc Time
|Incident/Event, 15 min to 1 hour.
|Incident Planning, 1 to 3 hours.
|Risk Assessment, 2 or more hours.
|Up to 3 days if weather persistent.
|Up to 6 days (evaluate forecast confidence).
|One week to 30 days.
|Single weather (wind and fuel moisture) scenario.
|Single weather (wind and fuel moisture) scenario over duration of run.
|Hourly, variable weather (wind and fuel moisture) over duration of run.
|Short term forecast plus ERC seasonal trend after that produce range of daily weather scenarios.
Max Spot Distance, Probability of Ignition.
Spotting Distance and Frequency
(one ember per node; spotting probability value higher than NTFB; start with .10% spotting probability).
Spotting Distance and Frequency
(16 embers per vertex; spotting probability value lower than STFB; start with .05%).
|Yes (like STFB)
Basic Fire Behavior Tools
Manual (Fireline) Methods:
Lookup Tables, Nomograms, and Nomographs are all direct implementations of the surface fire spread and spotting models and are constructed for use without computers.
- Lookup Tables and Fire Behavior Nomograms are constructed for only the original 13 fuel models and represent only surface fire behavior. They provide simple means to estimate fire behavior on the fireline based on observed fine fuel moisture, fuel model, wind, and slope. They can be found in the Surface Fire Section, Surface Fire Behavior Lookup Tables.
- Spotting Nomograms are for single torching trees only and do not account for terrain features. They can be found in Crown Fire Behavior Section, Spotting Fire Behavior.
- Fire Behavior Nomographs, PMS 436-3, include only the 13 original fuel models. Nomographs for Estimating Surface Fire Behavior Characteristics (Scott 2007) include both the 13 original fuel models (Anderson, 1982) and each of the additional 40 models implemented more recently (Scott and Burgan, 2001).
FLAME and the Campbell Prediction System are systems rooted in the concept that in the fire response to a fire, firefighters need to have a thought process that can help them identify what the fire is doing, how that relates to the fire environment (wind, slope, fire flammability), and what the upcoming changes will produce. Further, they focus on firefighter safety implications and encourage means of organizing thoughts for briefing firefighters.
While neither is in widespread use, they represent important attempts to blend the fire behavior prediction models and processes with fireline operations.
The Fireline Assessment Method, FLAME (Bishop, 2007) expects users to:
- Describe current fuels, winds, and terrain influences and the fire spread it is currently producing
- Identify what the Next Big Change will be during the burn period (slope reversal, fuel type change, forecasted change in the wind)
- Apply multipliers for windspeed, fuel, and slope to produce new estimates of fire spread to apply tactically.
Campbell Prediction System(CPS) identifies “three primary forces causing variations in fire behavior: wind slope and pre-heat.” It highlights the need to:
- Evaluate the specific “alignment of [these] forces” on each side of a fire and place on the landscape, and recognize the “fire signature, [or] the observed fire behavior” it produces.
- Identify “trigger points where a change in the alignment of forces will change the fire behavior [signature], creating either opportunity or danger.”
A desktop computer application that is composed of a collection of mathematical models that describe fire behavior, fire effects, and the fire environment based on specified fuel and moisture conditions. The program simulates rate of fire spread, spotting distance, scorch height, tree mortality, fuel moisture, wind adjustment factor, and many other fire behaviors and effects; it is commonly used to predict fire behavior in multiple situations.
Online Reference and Learning Resources
Due to periodic updating, users should check the Splash information found in the help menu to determine the version currently installed. Install the latest version. The latest version can be identified and downloaded from the BehavePlus Fire Modeling System website.
A collection of publications that support the BehavePlus Modeling System.
A comprehensive set of training resources can be found at the BehavePlus online reference Tips and Reference Materials.
An online self-paced course can be found among the self-study courses at the Frames Online Course System.
Creating a Workspace
To take full advantage of the BehavePlus system, users should consider recording their inputs, assumptions, and configurations within the BehavePlus file structure rather than on paper worksheets provided in the past. There are now enough options within the system that only knowing the fire environment inputs may not be sufficient to duplicate the results. Use these few guidelines to establish a BehavePlus Workspace and record all work, including documentation, by saving in the appropriate file format provided in the software.
In the BehavePlus File menu, the workspace submenu allows the user to open an existing workspace, create a new empty workspace, or clone the currently open workspace to a new location. The default workspace is located with the program files and is opened by default each time BehavePlus is opened.
Users should consider either creating a workspace on external storage (network folder or USB flash drive) or cloning the default workspace to one of those locations at the end of a work session when data files need to be shared, backed up, or archived.
There are individual folders for worksheet files, fuel model definition files, fuel moisture scenario files, individual run files that include system settings and modeling inputs, and unit settings. Work should be stored there.
Models and Tools Specific to BehavePlus
- Two-Fuel Model Projection.
- Special Case Fuel Models (Palmetto-Gallberry and Western Aspen).
- The Tools Menu includes Units Converter, Relative Humidity estimator, Fine Dead Fuel Moisture (Fosberg) Estimator, Slope from Map Inputs estimator, and Sun-Moon Calendar.
NEXUS 2.1 is crown fire hazard analysis software that links separate models of surface and crown fire behavior to compute indices of relative crown fire potential. Use NEXUS to compare crown fire potential for different stands, and to compare the effects of alternative fuel treatments on crown fire potential. NEXUS includes several visual tools useful in understanding how surface and crown fire models interact.
The NEXUS2 installation file is nexus2.1.exe. Save this file to your machine and install from there; admin rights required. Alternatively, you may download the NEXUS21.zip archive which contains the installation program plus the associated Readme.txt and ReleaseNotes.txt files.
Spatial Analysis Tools
There are a number of different fire behavior analysis systems that incorporate different combinations of the models referenced here. This a good guide to the different modeling systems, their inputs, and how they are used.
Scott, Joe H. 2012. Introduction to Wildfire Behavior Modeling. National Interagency Fuels, Fire, & Vegetation Technology Transfer.