Detecting an active fire is only one part of managing wildfire risk. Satellite wildfire monitoring is the broader, continuous discipline of tracking conditions before a fire starts, its behaviour while it burns, and the landscape it leaves behind. Each phase draws on a different combination of sensors, and each produces information that the next phase depends on.
Continuous risk monitoring before ignition
Fire risk is a function of fuel, weather and terrain, and all three can be observed from orbit well before a spark occurs. Live fuel moisture is estimated from optical indices such as NDMI, combined with recent rainfall and temperature history and regional drought indices. Fuel type itself comes from land-cover products such as Copernicus CORINE and the EFFIS fuel map, refined locally with forest inventories. Copernicus EFFIS also publishes a daily Fire Weather Index across Europe, giving a standardised, comparable measure of how primed a landscape is to burn on a given day.
Tracking an active fire from space
Once a fire is confirmed, the monitoring question shifts to where its perimeter actually is and how fast it is moving. Optical sensors such as Sentinel-2 deliver 10–20 metre imagery useful for perimeter mapping, but clouds and smoke frequently obscure the view during an active event. Sentinel-1 synthetic aperture radar sees through both, making it the only reliable all-weather, night-capable source for tracking a fire perimeter in near real time. Copernicus EMS Rapid Mapping supplements this with authoritative, activated-event damage grading once an incident is large enough to trigger it.
Assessing damage after containment
After a fire is contained, the same optical sensors that mapped fuel condition beforehand are used to grade burn severity, typically through the differenced Normalized Burn Ratio (dNBR) computed from pre- and post-fire Sentinel-2 scenes. This severity map matters well beyond the immediate incident: it informs recovery planning, erosion and landslide risk on burned slopes, and loss assessment for insurers.
How OrbiVigil does this
OrbiVigil maintains a layered environmental model — fuel type, live fuel moisture, terrain and daily fire-danger indices — as a standing "digital twin" of the landscape, updated continuously rather than rebuilt per incident. When a fire is confirmed, this twin becomes the input to a physics-based spread forecast, and Sentinel-1 and Sentinel-2 observations are used to re-initialise that forecast against the fire's actual observed perimeter as new imagery arrives. Post-containment, the same pipeline produces a burn-severity map without additional tasking. As with every OrbiVigil product, spread forecasts and severity maps are decision support: they inform the humans — incident commanders, air-operations officers, analysts — who make the call.
For the detection step that triggers this monitoring lifecycle, see wildfire detection. For the sensor physics behind the thermal signal itself, see thermal satellite fire detection. For how fire fits into OrbiVigil's broader multi-hazard approach, see natural disaster early warning.