Crews have been making steady progress in their battle against the Palisades and Eaton fires — with seemingly each new day bringing a further boost in containment.
But what do those figures mean, exactly?
Containment refers to how much of the fire’s edge, or perimeter, has been surrounded to the extent that firefighters believe they can stop the fire from expanding. Crews create control lines using natural barriers as well as man-made ones.
A natural barrier may be a river or creek. A road or highway can be another barrier. Human interventions can help contain a fire, such as using a bulldozer to scrape the vegetation off a swath of land to deprive the fire of fuel it could use to grow.
The percentage of containment is simply firefighters telling the public how much of the fire perimeter they believe will not go beyond their defenses.
That’s why even when a fire is 100% contained, it can still be burning, and firefighters stay to make sure it does not get out of control.
Containment of the Eaton fire, which has burned just over 14,100 acres in Pasadena and Altadena, jumped to 55% on Thursday morning, up from 45% a day earlier. At the Palisades fire, which has burned 23,700 acres, containment was at 22% Thursday morning, up from 17% a day earlier, according to the California Department of Forestry and Fire Protection.
But officials have stressed that there is still much work to be done in the fire zones before residents can return.
After a fire reaches 100% containment — which can take months, depending on the weather conditions, the blaze’s size and the area’s topography — crews work toward declaring the fire “controlled,” a Cal Fire spokesperson previously told The Times.
When a fire is controlled, it’s essentially out. Authorities will no longer assign crews to the blaze and will instead send a patrol out daily to ensure no scorched areas rekindle and start another fire.
