Firefighters from several area departments have beaten back a grass fire that was threatening several homes northwest of Arvada.
The fast-moving fire that erupted sometime after noon Tuesday grew to about 70 acres. The Jefferson County sheriff's office warned four-thousand households through the reverse 9-1-1 process to be ready to leave.
Sheriff's spokeswoman Jacki Tallman says flames had reached the foundations of some homes -- but firefighters aggressively defended the buildings and no structures were lost.
Denver T-V station K-M-G-H is reporting that firefighters sprayed water on houses and homeowners hosed down plants close to their homes.
Bulldozers and front-end loaders are being used to build fire lines around some of the houses.
The fire is more than 90 percent contained.
No injuries have been reported. Investigators are trying to determine what started the blaze.