The Federal Aviation Administration says nine people are missing and feared dead in the crash of a helicopter carrying firefighters in Northern California.

FAA spokesman Ian Gregor says the helicopter was carrying 11 firefighters and two crew members when it went down Tuesday night. Four people have been taken to a hospital with severe burns. Two are in critical condition.

Gregor says the Sikorsky S-61 chopper was destroyed by fire after crashing in a remote mountain location in the Shasta-Trinity National Forest.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP’s earlier story is below.

FORBESTOWN, Calif. (AP) _ A wildfire threatening rural homes in northern California more than doubled in size as flames were driven by unpredictable wind, forcing firefighters to briefly retreat.

The loss of valuable firefighting time allowed the two-day-old blaze near Forbestown in the picturesque Feather Falls area to grow from 1,000 acres to more than 2,500 acres in just a few hours Tuesday, said Anthony Brown, a spokesman for the California Department of Forestry and Fire Protection.

Elsewhere in Northern California, four firefighters were injured when their helicopter went down late Tuesday while fighting the remnants of a wildfire, said Shasta-Trinity National Forest spokesman Mike Odle.

Two of them were in critical condition Wednesday at the University of California Medical Center in Sacramento and the others were in serious condition at Mercy Medical Center in Redding, he said.

Odle said he did not immediately know if anyone else was aboard the helicopter, which crashed about 15 miles northwest of Junction City, west of Redding.

They were working a wildfire that had covered nearly 25 square miles in Trinity County, part of a larger complex of blazes that total 135 square miles. Officials said the complex was about 87 percent contained.

Another firefighter assigned to battle that series of wildfires was killed last month by a falling tree.

Containment of the blaze near Forbestown fell from 30 percent to 20 percent, Brown said.

“All the work of the fire crews came to a cease because of safety reasons,” Brown said. “When they retreated, it allowed the fire to consume a bigger area.”

People were told to evacuate homes between the middle and southern forks of the Feather River, which feeds into Lake Oroville, about 70 miles north of Sacramento.

Temperatures were expected to reach the triple digits Wednesday, Brown said.

Outside Yosemite National Park, the blaze that charred about 53 square miles, or 34,000 acres, was nearly completely contained by Tuesday evening, fire officials said. It had destroyed at least 28 homes and cost nearly $37 million to fight.