Wildfire field guide
What is spotting in a wildfire—and why do spot fires matter?
How burning embers can travel ahead of the main fire, ignite new fuels and create separate fire fronts beyond roads, rivers or containment lines.
Definition
Spotting is fire spread by transported embers.
Wildfire agencies use spotting for fire behavior in which burning embers or firebrands are carried through the air and ignite new fires beyond the zone of direct ignition from the main fire.
Process
Generation → transport → ignition.
US Forest Service research describes spotting as a chain of mechanisms rather than a single event.
Bark, twigs, leaves, cones and other burning material can be lifted from flaming vegetation or structures.
Convective currents can loft embers while ambient winds carry them away from the main fire front.
If a still-burning ember lands in sufficiently receptive fuel, it can establish a new spot fire.
Why it matters
Spotting can bypass barriers.
A road, river, fireline or treated strip can interrupt direct flame spread but cannot guarantee that airborne embers will not cross it.
New ignitions outside a control line can expand the perimeter and force crews to protect or build additional line.
Embers can enter gutters, vents, roof assemblies or receptive landscaping even before the main flame front arrives.
Multiple spot fires can grow and merge, potentially creating a new active front ahead of the original perimeter.
Spotting distance and successful ignition depend on ember characteristics, wind, plume behavior and the receiving fuel.
Current example
Dome Fire 2026 documented spotting.
The reviewed Dome Fire record preserves official reporting that gusty winds carried embers ahead of the main fire and produced spot fires to the north. Tecnobosque treats that as an observed behavior—not a forecast of where the perimeter will move next.
What it does not tell you
One spot fire is not a spread forecast.
- A reported spot fire proves an ignition occurred outside the main perimeter at a particular time.
- It does not by itself establish the future direction or distance of fire spread.
- It does not show that every ember generated a successful ignition.
- Spotting behavior should be interpreted with wind, fuels, terrain, fire intensity and timestamped perimeter data.
Sources