In what officials described as “mass devastation,” at least 1,000 structures were lost Thursday when a fire swept through the Northern California town of Paradise, forcing residents to run for their lives, LA Times reported.

The Butte County fire exploded from 10 acres to more than 10,000 acres in a matter of hours, taking direct aim at the town of 27,000 known as a popular retirement community.

“It has destroyed the town,” said Scott McLean, a spokesman with the California Department of Forestry and Fire Protection. By Thursday evening, it had charred 20,000 acres and left 15,000 structures under threat.

As people raced to safety, roads became choked with traffic, forcing some to flee on foot as the fire engulfed nearby homes and buildings. One hospital was evacuated — its patients were taken to nearby medical facilities — and parts of its campus were damaged by the flames.

At least two firefighters and multiple citizens have been injured, though officials would not say if anyone has died.

Named the Camp fire because it began near Camp Creek Road in Butte County, the blaze was first reported about 6:30 a.m., according to a Cal Fire spokesman. By midday, smoke had blanketed the town in darkness.

“It’s been nighttime for the last six hours, the smoke has come down so low and so heavy,” McLean said.