Update: Crews appeared to have gained control of the Sierra Fire Wednesday morning. Click here for an updated version of this story.
Original post: A brush fire grew rapidly in the foothills north of Fontana Tuesday night, with flames at times spreading onto the properties of nearby homes.
San Bernardino County fire officials said they were on scene near the intersection of Sierra and Riverside avenues, above the Sierra Heights neighborhood, just after 10 p.m. It's unclear when exactly the flames broke out.
The blaze grew to cover 20 acres within 15 minutes, the agency said.
It was being dubbed the Sierra Fire.
Rialto firefighters and Cal Fire San Bernardino crew members were also responding.
Aerial footage of the scene showed two large patches of flames near the 15 Freeway, not far from residential neighborhoods.
Authorities said no evacuations were being ordered, although firefighters could be seen working to extinguish embers that had made their way into shrubbery and trees outside at least two homes near Riverside Avenue.
Fire officials said they were stationing themselves to protect the homes.
Video from the ground showed embers being carried by the wind to spread flames across dry grass, and authorities confirmed that Santa Ana winds were contribution to the rapid rate of spread.
Earlier on Tuesday, winds in the fire area had been recorded at speeds of 56 mph, according to the National Weather Service.
Fire officials in Anaheim said local residents were reporting being able to smell smoke, which had likely been carried to Orange County from the Sierra Fire.
A red flag warning remains in effect over much of Southern California until 5 p.m. Wednesday.
Fire officials would continue battling the blaze overnight. Seven firefighting crews, 26 engines, three bulldozers and a sheriff's patrol helicopter were involved in the response, authorities said.
No further details were immediately available.