Pictures: Thousands flee, several hurt as wildfire scorches California

California Department of Forestry and Fire Protection firefighters try to stop flames from the Mill Fire from spreading on a property in the Lake Shastina subdivision northwest of Weed, California.

A plum of smoke covers the sky as the the Mill Fire approaches in Weed. Thousands of people remained under evacuation orders Saturday after a wind-whipped wildfire raged through rural Northern California, injuring people and torching an unknown number of homes.

The fire that began Friday afternoon on or near a wood-products plant quickly blew into a neighbourhood on the northern edge of Weed but then carried the flames away from the city of about 2,600.

Evacuees described heavy smoke and chunks of ash raining down. The blaze, dubbed the Mill Fire, was pushed by 56-kph winds, and quickly engulfed 10.3 square kilometers of ground.

The flames raced through tinder-dry grass, brush and timber. About 7,500 people in Weed and several nearby communities were under evacuation orders.

Governor Gavin Newsom declared a state of emergency for Siskyou County and said a federal grant had been received "to help ensure the availability of vital resources to suppress?the fire."

At about the time the blaze started, power outages were reported that affected some 9,000 customers, and several thousand remained without electricity late into the night, according to an outage website for power company PacifiCorp, which said they were due to the wildfire.

It was the third large wildfire in as many days in California, which has been in the grip of a prolonged drought and is now sweltering under a heat wave that was expected to push temperatures past the 100-degree mark in many areas through Labor Day.

Thousands also were ordered to flee on Wednesday from a fire in Castaic north of Los Angeles and a blaze in eastern San Diego County near the Mexican border, where two people were severely burned and several homes were destroyed. Those blazes were 56% and 65% contained, respectively, and all evacuations had been lifted.

The heat taxed the state's power grid as people tried to stay cool. For a fourth day, residents were asked to conserve power Saturday during late afternoon and evening hours.

The Mill Fire was burning about an hour's drive from the Oregon state line. A few miles north of the blaze, a second fire erupted Friday near the community of Gazelle. The Mountain Fire has burned more than 6 square kilometers but no injuries or building damage was reported.

The whole region has faced repeated devastating wildfires in recent years. The Mill Fire was only about 48 kilometers southeast of where the McKinney Fire - the state's deadliest of the year - erupted in late July. It killed four people and destroyed dozens of homes.

View of the Route Fire seen from the road near Castaic, Los Angeles County, California.

Scientists say climate change has made the West warmer and drier over the last three decades and will continue to make weather more extreme and wildfires more frequent and destructive. In the last five years, California has experienced the largest and most destructive fires in state history.