What "100% contained" actually means

Central Oregon · last checked 29 July 2026

Containment describes the line crews have dug, cut, or burned around a fire. It does not describe how much of the fire has gone out. A fire can be 100% contained and still be burning hard inside that line for weeks. That is normal. It is not a reporting error, and it is not somebody hiding something.

This is the single most common way people misread a fire map, including the one I built. It is why there is a permanent line of text above the fire list on the FireWatcher dashboard that says none of those fires are out.

I added that line because somebody local read "100% contained" on a fire a few miles from their place and took it to mean the fire was finished. It wasn't. Crews had a line around it and a hundred-odd people were still working it.

The four words agencies actually use

Fire agencies use a specific vocabulary, and the National Wildfire Coordinating Group (NWCG) publishes the definitions. These are quoted from the NWCG glossary, not paraphrased:

Control line

All built or natural fire barriers and treated fire edge used to control a fire. On the ground this can be hand line dug to mineral soil, a dozer line, a road, a river, a rock scree, or ground that has already been deliberately burned.

Contained

"The status of a wildfire suppression action signifying that a control line has been completed around the fire, and any associated spot fires, which can reasonably be expected to stop the fire's spread." — NWCG glossary

Controlled

"The completion of control line around a fire, any spot fires therefrom, and any interior islands to be saved; burned out any unburned area adjacent to the fire side of the control lines; and cool down all hotspots that are immediate threats to the control line, until the lines can reasonably be expected to hold under the foreseeable conditions." — NWCG glossary

Out

The end of it. No burning material anywhere in the fire area. On a big timber fire in the Ochocos that can be months after the last flame anybody saw from a road — stumps and duff hold heat, and a snag can smoulder into the fall.

Read those in order and the gap is obvious. Contained is the first of four steps. Almost every number the public sees is that first step.

What the percentage is measuring

It is the share of the fire's perimeter that has a completed control line the incident management team believes will hold. 40% contained means roughly 40% of the way around the edge is lined. It says nothing about the middle.

Two things follow from that, and they surprise people:

• The percentage can go down. If wind pushes fire across a line, that section is no longer contained and the number drops. It can also drop with no fire behaviour change at all, because a better map arrived — an infrared flight overnight or a new GPS track can lengthen the measured perimeter, so the same amount of line covers a smaller fraction of it.
• Acres and containment move independently. A fire can jump from 15,000 to 40,000 acres overnight and hold the same containment figure if the growth happened on the unlined side. Acreage also jumps for mapping reasons, not just fire reasons.

These figures come from the incident management team's own reporting into the interagency system, which is why they move in steps once or twice a day rather than continuously. Nobody is computing containment live from a satellite. It is a professional estimate, made by people standing on that line, and it is the best number available.

Central Oregon, 29 July 2026

Numbers from the NIFC WFIGS public feed the day this page was written, so you can see the pattern rather than take my word for it:

Brewer was at 100% containment with 1,111 people still assigned to it. Nobody keeps a thousand firefighters on a fire that is over. Green Mountain, eleven miles up the road from my house, was 100% contained with 114 people on it.

Statewide the same day: of 93 Oregon wildfires in NIFC's current-incident feed, 33 were listed at 100% contained. All 33 were still in the feed, because that feed only carries fires that have not been declared out — nationally, none of the 625 wildfires it listed had an out date on them.

Why fires vanish from the map instead of being marked "out"

FireWatcher asks NIFC for wildfires with no out date recorded (that is literally the filter: IncidentTypeCategory = 'WF' AND FireOutDateTime IS NULL). When an agency declares a fire out, the record leaves the current feed. So a fire does not turn grey on the map and sit there — it disappears.

The practical version: if a fire is on the FireWatcher list, it is not out, whatever its containment figure says. If it is gone from the list, either it was declared out or the feed changed shape, and I would rather tell you that plainly than dress up a guess.

One more thing that moves the numbers: complexes

When several fires burning near each other get managed by one team, they are grouped into a "complex" with its own record. The complex and its member fires can both exist in the data, and adding them together double-counts the acreage. FireWatcher counts the individual wildfires and skips the complex records, which is why a total here can differ from a headline that quotes a complex figure. Neither is wrong; they are counting different things.

What to watch instead of the percentage

If you live near a fire, containment is close to the least useful number on the page. These are better, and all of them are on the dashboard:

• Acres in the last 24 hours. Growth is the story. A flat acreage on a windy day means crews are winning.
• People assigned. It tracks how seriously the fire is being taken far more honestly than containment does.
• Which side it is growing on. A perimeter that is moving away from you is a completely different day than one moving toward you.
• Wind direction and speed. Fire goes where the wind sends it. See what a red flag warning means here.
• Satellite heat detections inside the perimeter. Heat still showing up deep inside a "contained" fire is exactly the interior burning that containment does not describe.
• Your county's evacuation level for your address. That is the number that actually tells you what to do, and it comes from your county sheriff — not from this site and not from the containment figure. Sign up at OR-Alert before you need it.

Sources

• NWCG Glossary of Wildland Fire (PMS 205) — "contained", and the entries for "controlled" and "control line".
• NIFC WFIGS public data (CC-BY 3.0) — the incident feed the acreage, containment, personnel and county figures above come from, queried 29 July 2026.
• InciWeb and Central Oregon Fire Info — the incident teams' own daily updates, which say in words what the percentage cannot.

Related: Oregon evacuation levels · Red flag warnings in Central Oregon · The aircraft over a Central Oregon fire · Where the smoke is coming from · All explainers