At 5,000 acres, the La Tuna fire is now the largest fire ever by acreage in the city of Los Angeles, with its "unpredictable" destructive potential dependent on shifting winds and erratic weather, the city's mayor and fire chief said Saturday morning. L.A. Mayor Eric Garcetti joined officials from his city and several others to update the public on the blaze, which has raged in the Verdugo Mountains since Friday afternoon. Garcetti and others acknowledged the huge scope of the fire, which will surely grow, but added that a strong ring of fire personnel around it are in a position to halt its path. "If things continue the way they are, despite the growth of this fire, I want to assure people that what we see on the ground is a fire we can contain," Garcetti told reporters at a command post at the scene. Officials said the "unpredictable" wildfire was 10 percent contained, as it threatened Burbank and Glendale. One home at Verdugo Crestline Drive and Alene Drive in Tujunga was destroyed, officials said. No one has been injured. "Our biggest concern is the wind and weather," L.A. Fire Chief Ralph M. Terrazas said. "If there's no wind, this is a relatively easy fire to put out." But if there are random shifts in wind, coupled with triple-digit heat and low humidity, the blaze could become much more destructive, he added. Garcetti tweeted at 9:02 a.m. that the wind was calm and there was "no immediate threat to homes." "It's a backing fire," Terrazas said, "meaning that it burns down a hill. And at the base of those hills, there's some homes. So we're making sure our fire engines are deployed so they can protect those homes when the fire gets there." Flames had crawled within a few hundred yards of homes as of Saturday morning, he said. Officials requested four air tankers from the state to join resources already working on the La Tuna fire, Terrazas said. It was not clear when the large aircraft may arrive. "Today we are still battling intense flames near structures especially in the city of Burbank," LAFD Capt. Branden Silverman said. "Last night we didn't see the fire lay down like we usually do in the evening. ... We definitely recommend people living in the fire area be ready to go, have a plan and when the fire does start to get near them, get that plan in motion." Officials also announced that 300 homes have been evacuated in Burbank, 180 in L.A. and some additional homes in Glendale. Officials urge residents in the fire area to be ready to evacuate if the call comes, and to take their pets with them. About 500 firefighters are working on the blaze now, additional resources have been requested from the state, and about 100 L..A. Officials also expect local firefighters are expected back from Texas soon, where they've been helping survivors from Hurricane Harvey. The city of Glendale announced mandatory evacuations in the Glenwood Oaks and Mountain Oaks areas at 11:30 a.m. Saturday, along with voluntary evacuations for the Whiteing Woods neighborhood. Officers went door to door overnight to enforce the mandatory evacuations. Burbank police directed evacuees to McCambridge Park at 1515 Glenoaks Blvd. in Burbank, and in Los Angeles an additional evacuation shelter was established at Sunland Recreation Center at 8651 Foothill Blvd. The city of Glendale opened an evacuation center at the Civic Auditorium, 1401 N. Verdugo Road, and another evacuation center was established at Crescenta Valley High School, 2900 Community Ave. in La Crescenta, officials said.