Temperatures dropped into the 60s in the San Bernardino Mountains, aiding firefighters trying to halt the Slide fire's move toward Lake Arrowhead, The Los Angeles Times reported. The weather was humid and overcast.

The 27,600-acre Santiago fire in east Orange County still threatened about 750 homes in and around Silverado Canyon early Saturday.

"Things are pretty rough," Rich Phelps, a U.S. Forest Service spokesman, said Friday, when the fire was reported 35 percent contained and sending flames 100 feet up the narrow canyon's walls.

Authorities sought the public's help in finding a white Ford F-150 pickup truck seen where the arson fire was started last Sunday. More than 490,000 charred acres, nearly 1,800 destroyed homes and 17 deaths are blamed on the week of fires.

"We are chasing down lots of tips, this one was impressive enough to present to the public," said Fire Authority Chief Chip Prather.

The reward for help leading to the conviction of the arsonist increased to $285,000 Friday.

Authorities Friday closed the emergency shelter at Qualcomm Stadium. About 115 people remaining there were transferred to other shelters.