"This moved so fast," said Darren Dalton, 51, who along with his wife and son had to get out of his house in the small town of Wrightwood. "It went from `have you heard there's a fire?' to 'mandatory evacuation' before you could take it all in ... Suddenly it's a ghost town."
Ash rained down on motorists from billowing black smoke, while aerial pictures from KNBC captured a roadside 'firenado' in which swirling gusts of wind sent flames twisting high into the air.
The Red Cross set up shelters for residents forced from their homes.
Shannon Anderson of Blue Mountain Farms horse ranch in Phelan had to load up and evacuate 40 horses as the fire approached.
"It's raining ash," Anderson told The Associated Press.
Two firefighters were hurt and briefly hospitalized when they became trapped while defending homes and assisting evacuations in the Swarthout Canyon area, San Bernardino Fire Department said.
The fire was zero percent contained and covered 28 square miles at 11 p.m. PT (2 a.m. ET) — only 12 hours after it began — according to CalFire.
The National Weather Service issued a red flag warning through Thursday night, saying strong winds, low humidity and warm temperatures meant "critical fire weather conditions" would contribute to "extreme fire behavior."
One the 800 residents in the Lytle Creek area told KNBC she was in the shower when deputies knocked on her door and asked her to evacuate.
The woman, who gave her name as Amber, said she grabbed what she could — including her dogs — and took off.
"There is no escape," she said. "This was the time for me to go."
Another evacuated resident, John Goodfried, told KNBC he watched air tankers flying missions over the blaze.
"If the smoke is heavy and thick and black you know it's burning something," he said.
The Los Angeles Sheriff's Department said a 98-year-old hospice patient was evacuated by helicopter from the Wrightwood area to the north of the wildfire.
Highway 138 to Lone Pine Canyon was closed, while San Bernardino Fire Department said there was no timetable for when Interstate 15 — the main link to Nevada — would reopen.
Night-time helicopters were assisting efforts to control the blaze, it said, continuing the work of 10 air tankers that doused the area fire retardant earlier in the day.
An 84-year-old local historian who uses a walker and is hard of hearing was saved after family members saw KNBC aerial pictures of his house surrounded in flames.
John Hockaday, who has penned books about the Cajon Pass and Route 66, wrapped his head in wet rags and held a hose with water from an emptying tank as the fire swept over his property, burned several cars and his mother-in-law's home, his cousin Ron Snow said.
Snow said he was watching an NBC4 live stream of the fire as flames surrounded Hockaday's house in Cajon Pass and reached out to the newsroom who contacted dispatch to get rescuers to Hockaday's location in a canyon called Lost Lake.
"He was surrounded by fire," Snow told the station. "Fire crews were dispatched. Now he's safe."
The number of fires in California has grown 20 percent over the last decade, rising from more than 4,800 fires in 2006 to nearly 5,800 fires in 2015, according to data from the California Department of Forestry and Fire Protection, KNBC reported.