What are Fire Progression Models?
These are computer programs that use inputs like weather, fuel, and topography and attempt to predict the spread of wildfires over a time horizon.
What are Fire Progression Models used for?
They can be used as one input into various operational decisions, including ordering or undertaking evacuations, requesting additional resources, preparing or shutting down at-risk infrastructure and facilities, or adjusting firefighting tactics.
Where can I find out more information about Fire Progression Models?
See the following links for more documentation on the models and their providers:
How accurate are Fire Progression Models?
Like most models, Fire Progression Models are simplifications of highly complex real-world conditions and interactions. Real-world variables are dynamic, and changes in weather, fire suppression activities, or other inputs influence real-world results. Watch Duty does not own or control Fire Progression Models, so we cannot provide insight into their quality. We consider them to be experimental and make no disclaimers about their accuracy, completeness, or timeliness. Proper tactical and life safety decision-making may be informed by Fire Progression Models but should also rely on a wide variety of other real-world information, including expert on-site judgment.
Why are models not available for a particular fire?
Providers have different conditions and constraints for running models. Certain models also have geographic coverage limitations. For example, WIFIRE only produces models for fires in California. Providers may also experience delays and other challenges while ingesting the required information to run or re-run the model.
Why does the fire location or perimeter for the Fire Progression Model look different than the incident location or fire perimeter in Watch Duty?
Fire Progression Models may use different data sources for incident locations and fire perimeters. In addition, Fire Progression Models rely on data available at the time the model was run, whereas Watch Duty updates fire locations and perimeters in real-time based on the most accurate and up-to-date information and sources.
What probability or confidence level do models use?
For models that produce many outputs with randomized inputs, only the 50th percentile (most common) result is shown in Watch Duty.
How often are Fire Progression Models re-run for fires?
Fire Progression Models are rerun by the provider based on their own guidelines. Watch Duty will display new runs as soon as they are available.
Why can I only see several hours' worth of predicted fire spread?
As with any model, the longer the time horizon used to predict events, the less likely the output is to be accurate because real-world variables change. Watch Duty caps the time horizon displayed to six hours since our focus is improving situational awareness and assisting near-term strategic and tactical, operational, and life-safety decisions. Some models provide less than six hours of fire spread, in which case, Watch Duty will show only as much as the model provides.
Does Watch Duty modify the outputs of model runs from the provider?
For WIFIRE, Watch Duty makes no modifications. For Pyregence, the model outputs raster “images” for a time horizon of several days. Watch Duty consumes only the first six hours of predictions and converts the raster “images” to vector polygons with smoothed outlines.