Undetermined Cause

Published by Tecnobosque · Editorial policy & corrections

Wildfire Knowledge Graph · Fire Investigation

Working definition

A cause status used when available evidence is insufficient to support one specific ignition cause to the required standard.

In plain language

A cause status used when available evidence is insufficient to support one specific ignition cause to the required standard.

Why it matters

Undetermined Cause is useful because it separates one specific part of wildfire behaviour, exposure, operations or evidence from nearby concepts that can otherwise be mixed together.

Primary terminology sourceSearch official NWCG glossary ↗

Tecnobosque explanation reviewed 12 September 2026. Source definitions are authoritative within their stated jurisdiction; the explanatory text above is an independent technical synthesis.

Undetermined cause: a legitimate conclusion, not a missing answer

An undetermined fire cause means the available investigation did not support a sufficiently reliable cause determination under the relevant methodology. It is not equivalent to ‘natural’, ‘arson’, ‘no investigation’ or ‘no evidence’. Different agencies may apply specific formal criteria to this status.

When reconstructing an incident, distinguish at least three states: investigation ongoing; investigation completed without cause determination; and public data that simply do not publish the cause field. These situations can all appear as blank entries in a summary but carry different meanings.

Timeline example: a September incident notice says ‘under investigation’, while a subsequent final report concludes ‘undetermined’. The later outcome should be added as a dated event, with the earlier notice preserved. Do not relabel the earlier notice as a final determination.

Speculating about a person, infrastructure owner or activity in an unresolved case can create real reputational harms. Unless a direct authoritative source supports it, leave potential causes as questions, not statements of fact.

Explore Evidence State, Known At and permanent incident records.