Wildfire Knowledge Graph · Fire Investigation
The reconstructed order of events by which an ignition source, first fuel and surrounding conditions produced a developing fire.
In plain language
The reconstructed order of events by which an ignition source, first fuel and surrounding conditions produced a developing fire.
Why it matters
Ignition Sequence is useful because it separates one specific part of wildfire behaviour, exposure, operations or evidence from nearby concepts that can otherwise be mixed together.
What is an ignition sequence?
An ignition sequence is the evidence-supported chain of circumstances and events that brings a competent ignition source, the first fuel ignited and an oxidizer together under conditions capable of starting combustion.
In wildfire investigation, the term answers a narrower question than the later incident timeline: what had to happen, and in what order, for ignition to occur?
Ignition sequence is not the fire chronology
These concepts should remain separate:
- Area of origin: where the fire began.
- Ignition source: what supplied the ignition energy.
- First fuel ignited: the material that began burning first.
- Ignition sequence: how source, fuel and conditions came together.
- Fire cause: the broader cause determination supported by the investigation.
- Fire chronology: what happened after ignition and in what temporal order.
Core reconstruction
Competent ignition source → energy transfer → first fuel ignited → oxidizer → sustained combustion
A defensible reconstruction should identify which links are directly documented and which remain inferred or unknown.
Evidence that may support the sequence
- Physical fire-pattern and origin evidence.
- Photographs, video and timestamped observations.
- Witness statements and emergency-call records.
- Electrical or mechanical examination.
- Weather, fuel and site conditions.
- Equipment records, telemetry or other time-stamped technical data.
Evidence status matters
Tecnobosque separates Observed, Derived, Inferred and Unknown information. An ignition sequence can therefore remain partially unresolved without collapsing into a single unsupported cause label.
Worked example
Consider a hypothetical equipment-related fire: a machine operates beside cured vegetation; a hot particle is produced; the particle reaches receptive fine fuel; sufficient energy is transferred; oxygen is available; combustion becomes self-sustaining. The ignition sequence is the chain connecting those events—not merely the statement “equipment caused the fire.”
Why this matters in Wildfire Black Box
Black Box records should preserve the ignition reconstruction separately from later suppression, rekindle, spotting, structure ignition and conflagration chronology. This keeps what was known, what was inferred and what was later confirmed auditable over time.
Do not confuse it with
- Ignition pattern: the arrangement or sequence used to intentionally ignite a prescribed fire.
- Ignition probability: likelihood that ignition occurs under stated conditions.
- Point or area of origin: location alone does not establish the complete ignition mechanism.
- Fire chronology: the later development of the incident through time.
Related concepts
Area of Origin · Material Claim · Wildfire Black Box Methodology · Fire Archive
Technical references
NWCG Glossary of Wildland Fire — Ignition Sequence
Tecnobosque Reference Concept · reviewed September 2026. Official terminology remains authoritative within its stated jurisdiction; this page provides an independent technical synthesis.