Authorities hope to start allowing residents to return by month's end to a Southern California community devastated by mudslides — if they can get most utilities restored by then.

Officials said Sunday that it will be a gradual process getting residents back into homes in Montecito, where at least 21 people were killed during flash floods Jan. 9. A 17-year-old boy and 2-year-old girl remain missing.

The coastal town's narrow streets are clogged with bulldozers and utility trucks as crews remove mud and boulders and rebuild drainage pipes and power lines.

Robert Lewin, director of Santa Barbara County's office of emergency management, said it may be into February before natural gas service is restored.

A major highway reopened Sunday after a nearly two-week closure caused by the mudslides.

Gov. Jerry Brown declared Monday a "Day of Remembrance of the Montecito Mudslides and ordered flags flown at half-staff over the state Capitol.

He called it California's deadliest flooding event in recent memory.

"As we remember those we lost in this disaster, we should also remember the injured, the missing and the survivors who may need our help in rebuilding their lives," his proclamation said.

Cottage Health system said three of the injured, including one in serious condition, remained in its hospitals Monday. The system admitted or treated and released a total of 28 injured patients after the flood.