California, Oct 25, 2019, SPA -- California firefighters on Friday sought to take advantage of a lull in winds to gain ground on a pair of fast-moving wildfires, including one that has forced the evacuation of about 50,000 residents in suburbs north of Los Angeles. California Governor Gavin Newsom on Friday declared a local emergency to assist in fighting that blaze and another one in the wine-growing region of Sonoma County that has destroyed nearly 50 structures and forced the evacuation of 2,000 people. In Los Angeles County, crews worked overnight to battle the Tick Fire that started on Thursday and has grown to char 4,300 acres (1,700 hectares), threatening 15,000 homes and businesses, officials said. The blaze has upended life in the suburban Santa Clarita Valley, about 40 miles (60 km) north of downtown Los Angeles, which has been used as the backdrop for many movies and television productions and is home to the Magic Mountain amusement park. "This is the largest evacuation that we've had in Santa Clarita," Los Angeles County Supervisor Kathryn Barger told a news conference, putting the number of people ordered to evacuate at 50,000. Smoke from the two fires was disrupting life in two of California's biggest cities. A smokey haze drifting toward the Bay Area of San Francisco prompted warnings to residents to stay indoors, close windows and use masks. Los Angeles officials closed dozens of schools in the San Fernando Valley, just south of the Tick blaze, because of fears over hazardous breathing conditions. --More 03:03 LOCAL TIME 00:03 GMT 0019 www.spa.gov.sa/w1197802