SAN DIEGO – A fast-moving wildfire forced the closure of Interstate 8 for several hours, but fire crews from around the county were able to prevent it from spreading to nearby homes.

The Jennings Fire started shortly before 2 p.m. on the shoulder of eastbound I-8 where it crosses over Olde Highway 80, Cal Fire San Diego Unit Chief Tony Meacham said. Red-hot particles from the catalytic converter of a passing vehicle ignited grass and brush by the side of the road, he said. The flames quickly roared up the hillside, scorching about 50 acres in the first 30 minutes.

Fire units from Cal Fire, Alpine and Lakeside arrived on the scene within minutes. As they began to fight the flames, the California Highway Patrol closed eastbound I-8 at Lake Jennings Park Road and westbound I-8 at Tavern Road.

Sheriff's deputies evacuated about 15 families whose rural homes were threatened by the fire. They were sent to an evacuation center set up at Joan MacQueen Middle School in Alpine and Granite Hills High School in El Cajon.

Seven air tankers dropped fire retardant on the flanks of the fire to slow its spread and four helicopters made repeated water drops over the fire, returning to nearby Lake Jennings to refill. On the ground, 43 engines and 250 firefighters worked to cut containment lines around the blaze on the steep, rugged hillside and douse burning brush.

By 5 p.m., crews had stopped the forward advance of the fire towards Alpine and the rural community of Crest and the danger to homes was over, Meacham said.

By 9 p.m., the fire was 10 percent contained and all evacuation orders were lifted, shelters were closed and residents could return to their homes.

Crews would remain on the fire line through the night and the mop-up operation would probably continue through Thursday, he said.

Westbound I-8 reopened at about 5 p.m. By 9:30 p.m., authorities reopened the eastbound lanes.