SAN BERNARDINO (CBSLA) — A brush fire was sparked by an illegal campfire in the San Bernardino Mountains Thursday, and forest officials say that it’s the second time such a fire happened this week.

The Fork Fire, which was reported by a volunteer fire lookout at Keller Peak at about 3:45 p.m. Thursday burned off East Flats Road in the Barton Flats area south of Big Bear. Firefighters were able to keep it to a quarter acre, and it has been 100% contained.

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Authorities say the mountains have seen an increase in visitors, and correspondingly, an increase in bad practices like setting up fires outside designated fire rings at developed campgrounds. According to forest spokesman Zach Behrens, there have been a 150% increase in illegal fires, from 33 in 2019 to 87 in 2020.

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Campfires built directly on the ground are always illegal, officials said.

“All it takes is a gust of wind to get it going again, where it can quickly grow into a full-blown wildfire threatening not only the forest’s resources and private properties, but the people who live, work and play in the forest as well,” officials said in a statement.

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California Campfire permits are free, and are obtained online after watching a short, educational video from CalFire. Not following the rules of the forest can be costly – a citation for violating fire restrictions is a federal offense punishable by a Class B misdemeanor, by a fine of up to $5,000 for an individual and $10,000 for an organization, or up to six months in prison.