Wildfire maps are becoming much more sophisticated.
For years, most wildfire maps focused on showing the location of an active fire, its perimeter, satellite-detected hotspots, evacuation areas, and sometimes smoke conditions. Those maps remain critical during an emergency, but a new generation of geospatial technology is attempting to answer a different question:
Where is a wildfire most likely to happen next?
Building a predictive wildfire risk map requires much more than plotting historical fires or looking at tomorrow's temperature.
Wildfire risk is created by the interaction of weather, vegetation, drought, terrain, ignition sources, infrastructure, and human activity. A useful predictive model therefore needs to combine multiple geographic datasets into a continuously updated risk surface.
Think of the system as a stack of transparent maps.
One layer shows wind.
Another shows vegetation.
Another shows drought.
Another shows power lines.
Another shows historical fires.
Individually, each layer tells only part of the story. Overlay them and a much clearer picture of wildfire risk begins to emerge.
Here are 10 of the most important data layers for building a predictive wildfire risk map.
1. Weather Data
Weather is one of the most important components of wildfire prediction because fire conditions can change dramatically within hours.
A predictive wildfire model should incorporate variables including:
- Air temperature
- Relative humidity
- Wind speed
- Wind direction
- Precipitation
- Atmospheric pressure
- Recent weather trends
- Forecast weather conditions
Wind deserves particular attention.
Strong winds can dry vegetation, increase fire intensity, carry embers ahead of a fire, and dramatically increase the speed at which flames move across a landscape.
A location experiencing 95°F temperatures and dry vegetation might already have elevated fire risk.
Add 40-mph winds and extremely low humidity, and the situation becomes significantly more dangerous.
The important distinction for predictive mapping is that weather should not simply represent current conditions.
Forecast data can be incorporated so the map attempts to show what wildfire risk could look like several hours or days into the future.
A wildfire risk map could therefore behave somewhat like a weather forecast:
Current wildfire risk
6-hour wildfire risk
24-hour wildfire risk
48-hour wildfire risk
This would allow emergency managers to see dangerous conditions developing before they arrive.
2. Vegetation and Wildfire Fuel Data
Wildfires need fuel.
In many environments that fuel consists of grasses, brush, shrubs, trees, fallen branches, dead vegetation, and accumulated organic material.
But not all vegetation burns the same way.
Grasslands can produce extremely fast-moving fires, while forests can contain enormous quantities of combustible material. Dense brush can create another type of fire behavior.
A predictive wildfire map therefore needs detailed information about the vegetation covering the landscape.
Important variables include:
- Vegetation type
- Vegetation density
- Canopy coverage
- Dead vegetation
- Fuel loading
- Fuel continuity
- Vegetation height
- Recent vegetation changes
Satellite imagery is particularly valuable for monitoring vegetation across large geographic areas.
The important question isn't simply:
Is vegetation present?
It is:
How much combustible fuel is present, what type is it, and what condition is it in?
Those factors can dramatically influence both wildfire probability and potential fire behavior.
3. Fuel Moisture
Two areas can contain almost identical vegetation but have completely different wildfire risks because of moisture.
Wet vegetation is much harder to ignite.
Extremely dry vegetation can become highly combustible.
Fuel-moisture measurements attempt to determine how much water is contained within vegetation and dead organic material.
A predictive system might monitor both live and dead fuel moisture.
This is especially important following extended periods of hot, dry weather.
Imagine a region that has gone weeks without meaningful rainfall.
Satellite observations indicate vegetation stress.
Ground stations show declining fuel moisture.
Temperatures remain above normal.
Relative humidity continues falling.
Even before a fire starts, these variables could cause the area to move from moderate to high or extreme wildfire risk.
Fuel moisture effectively helps answer one of the most important predictive questions:
If a spark occurs here today, how easily could the surrounding landscape ignite?
4. Drought Conditions
Drought creates wildfire risk over a much longer timeframe than hourly weather.
A single hot afternoon does not necessarily create extreme wildfire conditions.
Months of below-normal precipitation can.
A predictive wildfire model should therefore incorporate drought measurements alongside real-time weather information.
Important drought-related variables can include:
- Precipitation deficits
- Soil moisture
- Snowpack
- Streamflow
- Groundwater conditions
- Vegetation stress
- Duration of dry conditions
This allows the system to understand the environmental conditions leading up to a particular day.
Consider two locations experiencing identical weather:
Temperature: 96°F
Humidity: 15%
Wind: 25 mph
One received significant rainfall two weeks ago.
The other has experienced severe drought for months.
Their wildfire risk may be dramatically different.
A predictive model needs that historical environmental context.
5. Topography: Elevation, Slope and Aspect
Wildfire behavior is heavily influenced by terrain.
Fire generally moves faster uphill because flames can preheat vegetation above them. Steep slopes can therefore create conditions for rapid fire spread.
Three particularly important topographic variables are:
Elevation — the height of the terrain.
Slope — how steep the terrain is.
Aspect — the direction a slope faces.
Aspect matters because sunlight exposure influences temperature and vegetation moisture.
In parts of the Northern Hemisphere, south-facing slopes often receive more direct sunlight and can become warmer and drier than nearby north-facing slopes.
Digital elevation models allow GIS systems to calculate these variables across enormous geographic areas.
Terrain information can also help estimate where a fire could move after ignition.
That means topography is useful for both ignition-risk mapping and fire-spread modeling.
6. Historical Wildfire Locations and Perimeters
One of the best ways to understand future wildfire risk is to study the past.
Historical wildfire databases can show:
- Previous ignition locations
- Burn perimeters
- Fire frequency
- Fire size
- Fire causes
- Seasonal patterns
- Spread direction
- Weather during previous fires
- Areas repeatedly affected by wildfire
When thousands of historical incidents are placed on a map, geographic patterns can become visible.
Some corridors may repeatedly experience fires.
Certain terrain types may show higher ignition frequencies.
Other areas may experience relatively few ignitions but produce extremely large fires when they occur.
Historical fire data is especially valuable for machine-learning systems.
The model can examine conditions that existed before previous fires and search for similar patterns occurring today.
Essentially, historical wildfire maps become the training data for future wildfire prediction.
7. Lightning Strike Data
Not every wildfire is caused by humans.
Lightning is an important natural ignition source, particularly across remote areas of the western United States and Canada.
Real-time lightning detection networks can identify the location and timing of individual lightning strikes.
That creates another valuable geographic layer.
A predictive model could combine lightning observations with vegetation moisture and weather.
For example:
A lightning strike in an area that recently received heavy rain might receive relatively low concern.
A lightning strike into extremely dry vegetation during drought conditions could receive a much higher risk score.
Lightning-caused fires can also smolder before becoming obvious.
That means lightning data could be used to identify geographic locations requiring additional satellite, camera, aircraft, or ground monitoring.
Instead of searching millions of acres equally, authorities could focus attention on the locations where ignition is most plausible.
8. Power Lines and Electrical Infrastructure
Electrical infrastructure is another important potential ignition layer.
A GIS database could include the locations of:
- Transmission lines
- Distribution lines
- Utility poles
- Transformers
- Substations
- Electrical corridors
- Generating facilities
Those locations could then be compared with vegetation, wind, drought, and historical fire information.
Imagine a power line crossing a heavily vegetated canyon.
The vegetation is extremely dry.
Humidity is forecast to fall below 10%.
Wind gusts could exceed 50 mph.
Even though no wildfire currently exists, the combination of those conditions could cause the corridor to receive an extreme risk classification.
Utilities could potentially use this information to prioritize inspections, vegetation management, equipment monitoring, staffing, and other wildfire-prevention measures.
This demonstrates an important concept in predictive mapping:
Risk often comes from the intersection of datasets rather than any individual dataset.
A power line by itself isn't necessarily dangerous.
Dry vegetation by itself doesn't guarantee a wildfire.
Wind doesn't automatically create a fire.
But power infrastructure + dry vegetation + extreme wind + low humidity can create a much more significant risk profile.
9. Roads, Population and Human Activity
Humans are another major component of wildfire risk.
Roads, recreation areas, campgrounds, construction zones, communities, and other areas with frequent human activity can create potential ignition opportunities.
A predictive wildfire map could therefore include geographic layers showing:
- Roads
- Highways
- Trails
- Campgrounds
- Recreation areas
- Construction activity
- Railroads
- Agricultural areas
- Population density
- Development patterns
Historical ignition data could then determine whether proximity to particular types of human activity correlates with wildfire occurrence.
For example, if historical fires repeatedly begin near certain transportation corridors during dry periods, those locations could receive additional weight in the predictive model.
Population information is also important for understanding consequences.
A wildfire in a remote region may threaten ecosystems and natural resources.
A similar wildfire near thousands of homes could become a major life-safety emergency.
This introduces another important mapping layer: the wildland-urban interface, where human development meets or mixes with wildfire-prone vegetation.
10. Satellite and Ground Sensor Data
The final layer brings many of the others together: real-time observations.
Satellite systems can monitor enormous geographic areas and identify changes in vegetation, land surface conditions, thermal activity, smoke, and active fires.
NASA's Fire Information for Resource Management System, or FIRMS, distributes active-fire information derived from instruments including MODIS and VIIRS. VIIRS active-fire products can provide observations at approximately 375-meter resolution, while MODIS products are approximately 1 kilometer. NASA also makes Landsat-derived active-fire products available at finer spatial resolution for supported areas and periods.
NASA FIRMS distributes these observations through downloadable GIS datasets, maps and web services, making satellite fire information particularly useful for geospatial applications.
Ground sensors provide a different advantage: extremely localized measurements.
A sensor network could monitor:
- Temperature
- Humidity
- Wind
- Soil moisture
- Fuel moisture
- Smoke
- Particulate matter
- Atmospheric conditions
Imagine thousands of sensors positioned throughout wildfire-prone areas.
Each sensor becomes another point on the map.
If several sensors suddenly report rapidly declining humidity, increasing wind and unusually dry environmental conditions, the predictive model could increase the wildfire risk score for that specific area.
Satellites provide the broad view.
Sensors provide local detail.
Together they can create a much more responsive wildfire monitoring network.
Turning 10 Data Layers Into One Wildfire Risk Score
The real power of predictive wildfire mapping comes from combining these datasets.
Suppose a geographic grid cell has the following conditions:
Temperature: Extremely high
Humidity: Extremely low
Wind: High
Vegetation: Dense
Fuel moisture: Critically low
Drought: Severe
Terrain: Steep
Historical fires: Frequent
Lightning: Recent strike nearby
Infrastructure: Power lines present
That location should probably not receive the same wildfire risk score as a nearby area with moist vegetation, flat terrain, no recent lightning and little historical fire activity.
A predictive model could assign a weight to each variable.
Conceptually, the calculation might resemble:
Wildfire Risk = Weather + Fuel + Moisture + Drought + Terrain + Ignition Probability + Historical Risk + Exposure
Machine learning could make the model significantly more sophisticated by determining which combinations of variables have historically been associated with wildfire ignition and rapid fire growth.
The final result could be converted into an easy-to-understand map.
Green — Low Risk
Yellow — Moderate Risk
Orange — High Risk
Red — Extreme Risk
Instead of displaying hundreds of complicated environmental variables, the map would convert them into actionable geographic intelligence.
Predictive Wildfire Maps Need to Be Dynamic
One of the biggest differences between traditional hazard maps and predictive wildfire maps is time.
A traditional wildfire hazard map might remain relatively unchanged for months or years.
A predictive wildfire map could change every few minutes.
At 7:00 a.m., a location could have moderate risk.
At noon, rising temperatures and declining humidity might move it to high risk.
At 3:00 p.m., unexpectedly strong winds could push it into extreme risk.
By midnight, cooler temperatures and increased humidity could reduce the threat.
This makes predictive wildfire mapping much closer to weather forecasting than conventional static mapping.
Users shouldn't just be able to ask:
Where is wildfire risk high?
They should eventually be able to ask:
Where will wildfire risk be highest tomorrow afternoon?
From Wildfire Mapping to Wildfire Intelligence
NASA FIRMS demonstrates how quickly satellite observations can already be integrated into digital mapping systems. FIRMS distributes active-fire observations from MODIS and VIIRS, with global near-real-time data generally available within hours and faster services available in the United States and Canada.
But satellite fire detection primarily tells us where a thermal anomaly or potential fire has already been observed.
The next major step is moving further back in the emergency timeline.
A predictive wildfire intelligence platform would combine satellite information with weather forecasts, vegetation, drought, terrain, historical fires, lightning, infrastructure, human activity, and sensor measurements.
Instead of simply answering:
Where is the wildfire?
The map begins answering:
Where are the conditions for the next wildfire developing?
That distinction could fundamentally change wildfire management.
Emergency managers could pre-position resources.
Utilities could increase monitoring.
Fire departments could adjust staffing.
Communities could increase preparedness.
Land managers could restrict high-risk activities.
And researchers could continuously improve prediction models as more environmental and wildfire data becomes available.
The future of wildfire mapping isn't just about creating better maps of fires.
It is about building geographic systems capable of understanding the conditions before the fire begins.
When weather, environmental sensors, satellites, infrastructure, terrain, and historical wildfire records are combined into a single geospatial platform, a wildfire map becomes something much more powerful:
an early-warning system.
