A fast-moving wildfire that broke out on Thursday in northern California has forced the evacuation of nearly 4,000 residents, racing across at least 600 acres within just a few hours, officials say.



The Mountain fire, which erupted on the outskirts of a national forest in northern California, has threatened 1,110 homes and structures. As of Friday morning the fire was 40% contained , according to Cal Fire.

The cause of the fire is under investigation.

Photos of the blaze posted on Twitter by the Shasta county sheriff’s office showed thick black and gray smoke billowing into the area over a highway near the Shasta-Trinity national forest.

“Jones Valley and Bella Vista area residents! This situation is very fluid and rapidly changing, if you do not see your road listed but feel you are in danger YOU MAY EVACUATE to Shasta College Gymnasium,” the sheriff’s department said in a separate tweet.

The Mountain fire is threatening thousands of homes and forcing evacuations. Photograph: AP

The Shasta College campus was closed along with Highway 299 and about a dozen smaller roads. Residents of small communities in the path of the flames were told to evacuate or be prepared to flee on short notice.

California was hit by some of the deadliest and most destructive wildfires in a century last year and state officials have warned this year’s fire season could be similarly intense.

The Camp fire, which broke out in Butte county in November and overran the town of Paradise, killed 86 people and left thousands of others homeless. State fire investigators determined that the Camp fire was sparked by Pacific Gas & Electric Co transmission lines.

The Mountain fire broke out on the same day that Bernie Sanders, the senator and Democratic presidential candidate, unveiled his $16.3tn climate change plan and toured Paradise, which he called a “wake-up call for our entire nation”.

“Climate change is a major, major crisis for our country, and the entire world, and one of the manifestations of that crisis is what happened here,” Sanders said as he walked through a burned-out mobile home park in Paradise alongside people who lost their homes in last November’s deadly blaze.