DENVER – Colorado authorities say they have told rural residents in the foothills west of Denver to be ready to evacuate their homes if a new wildfire spreads.

Jefferson County Sheriff’s Office spokesman Mike Taplin said Saturday that officials have closed a portion of U.S. Highway 6 west of Golden to fight the small fire.

The blaze was discovered Friday in rugged terrain near Bald Mountain. It produced billowing smoke that could be seen from downtown Denver.

Officials are investigating the cause.

Taplin says the fire didn’t grow overnight and that fire officials expect the blaze to be contained later Saturday.