A fire ignited Thursday afternoon near the southwestern bank of Lake Piru in Ventura County and by evening had burned nearly 300 acres. The flames stranded half a dozen boaters, who were forced to shelter in place lakeside, officials said.

The blaze, dubbed the Felicia fire, threatened three to five structures, including homes and a U.S. Forest Service fire station. Video from OnScene.TV showed roaring flames leaping into the air. Fire was burning dangerously close to a house as the afternoon wore on.

All threatened structures have crews assigned to protect them, said Andrew Dowd, a Ventura County Fire Department public information officer.

The fire had burned 301 acres and was 14% contained as of 8 p.m.

Dowd told The Times that more than 500 assigned firefighters “were making good progress” and the fire’s forward advance had been stopped.

“Steep, rugged terrain with limited access is hampering firefighting efforts,” the department wrote in an X post updating the fire’s progress.

The Ventura County Sheriff’s Department ordered an evacuation of the western side of the lake and closed Piru Canyon Road. Around 15 people were evacuated from the lake’s recreational areas, including a campground and the nearby canyon.

A firefighting bulldozer works against advancing flames in the Ventura County blaze on Thursday afternoon.

(Eric Thayer / Associated Press)

Six boaters were unable to leave before roads closed, Dowd said, and sheltered at the marina parking lot north of the fire until park rangers were able to escort them out around 5 p.m.

The fire started around 1 p.m., and its cause still under investigation, Dowd said. No injuries have been reported.

Video released by the Ventura County Fire Department showed workers clearing brush while helicopters dropped water on the fire in the distance.