"This fire has danced around like nothing I've ever seen," Los Angeles City Council Member Tom LaBonge told reporters, adding that the fire had destroyed a terraced garden known as Dante's View.
The park is in the Hollywood Hills, about 10 miles north of downtown Los Angeles. It includes golf courses, tennis courts, the city's zoo and botanical gardens and the copper-domed Griffith Park Observatory.
The bright orange glow of the fire provided a striking backdrop for the white facade of the observatory into the evening hours.
Visitors and nonessential workers were ordered to leave the zoo when the fire broke out, but none of the facility's animals were being evacuated, spokesman Jason Jacobs told CNN.