Fire containment: What does it really mean?

Jun 28, 2021

California is in peak wildfire season and with higher temperatures, vegetation gets drier and is more prone to burning. Weather conditions, especially winds, means there’s a higher risk of a fire starting and spreading.

When a fire breaks out, containment is often the percentage that goes along with it. But, a higher percentage doesn’t mean a fire isn’t still burning.

James Blattler, the public information officer for the San Luis Obispo City Fire Department, said containment is all about the perimeter of the fire.

“So that percentage typically will be how much of the perimeter of the fire has a solid containment line in,” Blattler said. “So if you have a fire going on and the fire officials say, ‘Hey if you walk the perimeter of the fire and it’s this certain amount of length, we have this much of this length with a solid containment line’ – that’s kind of where they’ll derive that number.”

When a fire is 95% contained, that doesn't mean the fire is 95% out, it means firefighters have control of 95% of the fire’s perimeter.

“If you see a fire that has 20% containment, what you’re seeing there is 80% of the perimeter of that fire is still uncontrolled and it's still actively burning so there is going to be a lot of effort continuing on those fires,” Blattler said.

Even when agencies report that a fire is 100% contained, Blattler said this doesn’t mean the crews are done working.

“So you might have 100% containment and you’ll still see fire crews out there potentially putting out certain hot spots and making sure – for several days – making sure, you know, something might appear to be out at a given time and a few days later the winds pick up and maybe catch some embers that were sitting on the interior of the burn area and smoke starts to develop," Blattler said. "Fire agencies are really careful any time these vegetation fires happen and they'll continue to monitor it for several days until they’re very confident that the fire is good and out.”

Abigail Craig, a San Luis Obispo resident, witnessed firefighters responding to a recent fire on the Cuesta Grade and said it was a humbling experience.

“It made me feel really nervous for the upcoming summer, knowing that the fire season is going to be really rough this year,” Craig said. “It also made me feel very humbled and grateful seeing people fight a fire so close to me. They really just put themselves out there and I’m grateful for them.”

Blattler said that early detection and reporting are especially important for crews to put out a fire before it becomes bigger. The San Luis Obispo City Fire Department is also asking for the community’s help reporting fires in open spaces or near creeks.

If you see smoke or a fire call the 24/7 non-emergency dispatch line at (805) 781-7312. But, if the fire appears out of control, dial 911 immediately.

For more information about wildfires and how to prepare visit the City’s website.