A fire of unknown origin leveled a three-story wood frame residence south of Interstate 90 at the Tarkio exit Monday morning.
Neighbors noticed what they believed to be smoke sifting from house's vents about 8 a.m., according to Scott Waldron, chief of the Frenchtown Fire Department, but they couldn't see any flames.
By 9:45 a.m., when the Mineral County Sheriff's Department called Frenchtown Fire for assistance, there was little chance of saving the structure.
"Once it was vented, it was fully involved in a matter of minutes," Waldron said, adding that all firefighters could do was spray the water they carried on their tenders, then watch the structure burn.
The house, which was unoccupied at the time of the fire, is owned by John Bedell, who is out of town.
There were no injuries, but the blaze sparked a one-acre grass fire that was extinguished by the U.S. Forest Service, Waldron said.
"Residents who build in areas with no fire protection and a long ways from water supply should put residential sprinklers in their homes," he said. "There's just no way to provide adequate protection for homes in that area."