CONIFER, Colo. -- A semitrailer ran off U.S. Highway 285 Friday morning and crashed into a building, catching fire.

The Colorado State Patrol said just before noon that the truck driver was found dead in the burned wreckage.

Emergency crews closed the highway for several hours to allow fire and rescue units to respond. The highway was re-opened at 12:20 p.m., with one lane of traffic in each direction.

The crash was reported shortly before 10 a.m. about three miles west of Conifer in the Kings Valley area. The crash happened across from the Long Bros. service station, according to eyewitness Caroline Harrison.

The building that was hit is an old fire house that was being used as a garage.

Harrison said the front of the semitrailer was inside the building and both burned. The fire was almost extinguished by 10:30 a.m.

Another witness to the crash said she is grateful to be alive.

"We were heading northbound on 285 and he was heading southbound. He crossed over into our lane of traffic and was heading head-on to us," said Angela Roe. "I started blaring my horn trying to get his attention, but he continued to pass."

The crash knocked out power along the Highway 285 corridor as far west as Fairplay. IREA said the crash knocked out a 44,000-volt transmission line that connects the Conifer substation with Fairplay. Power was restored just before noon.

According to the state patrol, sparks from the downed power line started the fire. Investigators also told 7NEWS that the same truck was pulled over earlier Friday morning by a Jefferson County deputy because it was seen weaving in and out of traffic.

The driver has not yet been identified. An autopsy will be needed to determine the cause of death.