DENVER (KDVR) — The Goltra Fire in Clear Creek Canyon west of Golden has grown to over 200 acres Wednesday and is believed to have been caused by a lightning strike.

On Tuesday afternoon, fire crews were called to a brush fire burning along U.S. 6 near tunnel 1 in Clear Creek Canyon. The Jefferson County Sheriff’s Office said the fire was most likely naturally caused by lightning that moved through the area. Witnesses told the sheriff’s office they saw the strike and the fire started shortly after.

On Tuesday the fire was only 10 acres in size and was not endangering any structures. However, on Wednesday, the sheriff’s office said the fire grew “significantly” overnight and additional resources have been ordered.

FOX31’s Jim Hooley spoke to the Jefferson County Sheriff’s Office who said the fire has grown to over 200 acres due to heavy down-canyon winds. A MMA flyover will be conducted later on Wednesday to give an exact acreage.

The Jefferson County Sheriff’s Office said the fire did make it to U.S. 6 overnight, so, when the road does reopen, drivers will see damage up to the road.

The sheriff’s office has assessed the risk posed by the fire, and fortunately, there are no homes in the area, only land.

Clear Creek Canyon and U.S. 6 remain closed while more crews move in to work and contain the blaze. U.S. 6 is closed from Highway 58 to Highway 119.

The Goltra Fire is believed to have received its name from the former or current landowner, according to the sheriff’s office.