LOS ANGELES (AP) - Powerful gusts pushed flames from a wildfire through Southern California canyons on Thursday, one of several blazes that burned near homes and forced residents to flee amid elevated fire risk for most of the region that prompted utilities to cut off power to hundreds of thousands.

The biggest blaze began late Wednesday as a house fire in Orange County’s Silverado Canyon, where gusts topped 70 mph.

“When crews arrived it was a fully engulfed house and the winds were extremely strong and they pushed flames into the vegetation,” said Colleen Windsor, a spokeswoman for the county’s Fire Authority.

The fire grew to more than 11 square miles and blanketed a wide area with smoke and ash.

Crews struggled in steep terrain amid unpredictable Santa Ana winds that sent flames racing across major roads. Two firefighters were hospitalized after being treated on scene for injuries, said Fire Chief Brian Fennessy. He said their condition was not immediately known.

Some homes were damaged in the fire and possibly destroyed, Fennessy said. He said he couldn’t immediately say how many homes were affected. Evacuations were ordered for thousands of residents of canyon and foothill neighborhoods near the city of Lake Forest - although some orders were later lifted - and residents of other nearby areas were told to be ready to get out.

There was no containment of the fire.

Numerous studies have linked bigger wildfires in America to climate change from the burning of coal, oil and gas. Scientists have said climate change has made California much drier, meaning trees and other plants are more flammable.

The Bond Fire about 50 miles southeast of Los Angeles is burning near the same area of October’s Silverado Fire, which forced tens of thousands of people to evacuate.

The new blaze broke out as Southern California utilities cut the power to tens of thousands of customers to avoid the threat of wildfires during the notorious Santa Anas.

Red flag warnings of extreme fire danger through Saturday were in place because of low humidity, bone-dry brush and the winds, which sweep down from the interior, the National Weather Service said.

Utilities in the populous region began cutting power Wednesday to customers as a precaution to prevent gusts from blowing tree limbs into electrical equipment or knocking down power lines, which have sparked devastating wildfires in recent years.

Southern California Edison had cut power to nearly 50,000 homes and businesses by Thursday evening and was considering de-energizing lines serving about 190,000 other customers in seven counties throughout the windy period, which could last into Saturday.