Cranston fire: What is containment and how does it work?

When a wildfire erupts, one of the first questions asked of fire officials is the containment percentage. What does that mean exactly?

Containment is when a fire break is created around the perimeter of a blaze and firefighters have “mopped up” into the burn area, explained Marc Peebles, public information officer for the Cranston fire Friday.

“This is done so as to ensure that the fire will not carry through or breach through that line,” he said.

The Cranston fire, which erupted Wednesday afternoon and burned through thousands acres, had been at 5 percent containment but that number dropped to 3 percent at one point. It’s now at 16 percent. However, that wasn’t because the first broke through the line, he said. It’s just a simple numbers issue.

“We had growth from 7,500 to 11,500 (acres) and our rate of containment didn’t keep pace,” he said.

Peebles expects containment numbers to increase overnight Friday after more accurate aerial mapping can be done of the burn area.

“They have been working really hard on this fire,” Peebles said.