Firefighters were slowly making progress in their battle to contain the inferno that has razed swathes of Los Angeles' Pacific Palisades neighborhood to the ground, but still-spreading flames threatened communities in the populous San Fernando Valley on Sunday.

The Palisades fire grew to 21,596 acres overnight, with evacuations expanding rapidly in Encino, Tarzana and Brentwood as flames threatened homes in Mandeville Canyon. Six helicopters flew throughout the night, dropping water on the blaze as it entered its 5th day Saturday. Containment grew from 8% to 11% overnight, according to Cal Fire.

The Palisades Fire, the most destructive wildfire in Los Angeles history, edged closer to one of the city’s major population centers on Friday: the San Fernando Valley. Sky5 footage showed the fire’s northern flank burning toward Mulholland Drive in the Santa Monica Mountains,