Wildfire Simulation Technology – Part 2

In the summer of 2003, a wildfire was threatening the Montana town of Hungry Horse. Several simulations were run by scientists who had combined data on the conditions of the fire, fuel, and weather to provide a forecast of what the fire would do.


FlamMap is a fire behavior mapping and analysis program that computes potential fire behavior characteristics (spread rate, flame length, fireline intensity, etc.) over a landscape under constant weather and fuel moisture conditions. This software creates digital maps of potential fire behavior characteristics like spread rate, flame length, and crown fire activity, for given environmental conditions (dead-fuel moistures, mid-flame wind speeds, and solar irradiance). These digital maps (which can include fire perimeters, fire behavior characteristics, and information regarding fuel moistures used during the simulation) can be viewed in FlamMap or exported for use in a GIS programs like ArcMap, as images, or to a word processor program (all of which would be handy for sharing with interested parties during an incident). As with FarSite, FlamMap can be downloaded to a personal computer for free. More information is available at http://www.firemodels.org/index.php/national-systems/flammap.

FSPro [Fire Spread Probability] is a different fire modeling system and is contained within the Wildland Fire Decision Support System (WFDSS),” explained McHugh. “Unlike the others, which you can install and run on a laptop or desktop computer, FSPro cannot.”

Also the output from the FSPro model is much different than the previously mentioned decision support system. “Rather than representation of fire growth, FSPro produces a probability surface that offers information about the probability of a fire reaching or impacting a point of concern within the specific time frame used for the simulation,” said McHugh. This probability surface can then be intersected with values of concern such as structures, powerlines or critical wildlife habitat, thus allowing for a true risk-based decision-making process. “It is very computationally intensive and utilizes very fast computers that are centrally located along with all the data required to run the model. Access to this system is limited and it is used to help in the decision-making process of real-time fires,” he added. To learn more about FSPro and WFDSS, visit the USFS website at https://wfdss.usgs.gov/wfdss/WFDSS_Home.shtml.

LandFire is the crucial “silent partner” in making these fire simulations possible. “We’re highly dependent on LandFire data for all the simulations we do, and the quality of the LandFire data is improving with each generation,” McHugh confirmed. “It provides seamless, consistent data layers, including fuel types, fire regime classification, and other geospatial layers of data critical to using geospatial decision support systems, such as FarSite, FlamMap, and FSPro.” Anybody can access LandFire data at http://www.landfire.gov.

And although these simulations are as realistic as software modelers can make them, there is still room for improvement. “Fire models don’t provide detailed information or ‘the answer,’ but rather information for the decision-maker to make a more informed decision. However, this does not mean that at times we will not have informed failure,” McHugh said, with a cautionary quote from George Box, “All models are wrong, but some are useful.

The picture wouldn’t be complete, however, without adding a couple of additional programs.

WindNinja simulates wind across the landscape using flow dynamics engineering that creates what you’d expect wind to do,” said Laurie Kurth, a Fire Applications Specialist in the Wildland Fire Management Research Development & Application group at Rocky Mountain Research Station, who leads the development of training for use in the S495 training program. “We also have a unit within the course for working with ArcMap.”

If you are interested in finding out more about how the S495 program can help you understand these advanced modeling tools, go to http://frames.nbii.gov/portal/server.pt/community/fire_behavior/212/s-495/2840.

Canada

With an average of 8,000 fires per year, costing between $500 million and $1 billion to extinguish, Canada has also been active in developing wildfire prediction software. Their answer to this problem is Prometheus, a deterministic wildland fire growth simulation model based on the Fire Weather Index (FWI) and Fire Behaviour Prediction (FBP) sub-systems of the Canadian Forest Fire Danger Rating System (CFFDRS). It produces a GIS model that contains spatially explicit fire behavior and spread outputs given heterogeneous forest fuel, topography and weather conditions. Fuel types and weather can be modified by users to evaluate a variety of scenarios and the data inputs can be imported from files or created manually.

Not only can Prometheus provide operational decision support by predicting wildfire behavior, users can also conduct “what-if” scenarios to determine the threat of potential wildfires to values at risk; it can assist in setting up fire management zones, and identifying opportunities for the use of prescribed fire; and supplement wildfire training and education programs, among other uses.