GAVIOTA, Calif. —  Hundreds of residents in Southern California evacuated from a wildfire that has burned about 7,500 acres were allowed to return to their homes Sunday night, authorities said.

The Santa Barbara County fire was about 20 percent contained and could be slowed down by a moist low pressure system expected to drift into the region, said Barry Peckham, spokesman for the Los Padres National Forest (search).

The evacuation order was lifted Sunday night and a roughly 3-mile-long stretch of Highway 101 partially reopened after an earlier closure, Peckham said.

He said one home was destroyed and three outbuildings have been damaged. Two oil refineries were threatened, but undamaged. The fire also damaged train trestles owned by Union Pacific Railway (search) between San Luis Obispo and Santa Barbara.

There were no reports of any injuries.

The blaze threatened 150 homes in the gated community of Hollister Ranch (search), as people were also ordered to leave three state beaches, said Jan Purkett, a spokeswoman for the county fire department. About 500 people in the community were evacuated.

The fire broke out before noon Saturday in a section of the Gaviota Pass, about 27 miles north of Santa Barbara, and burned across narrow canyons and steep hillsides covered with chaparral.