A wildfire kept raging in Boulder, the U.S. state of Colorado on Tuesday after prompting the evacuation of more than 3,000 people one day earlier, authorities said.

Since its outbreak on Monday, the fire has scorched 3,500 acres (about 1,418 hectares) of land and destroyed dozens of homes near Boulder, including some that belonged to firefighters, according to the Boulder Sheriff's Department (BSD).

Aided by a spotter plane, hundreds of firefighters were battling the fire west of Boulder as more than 3,000 evacuees waited to learn whether their homes survived overnight, BSD spokesman Rick Brough said.

The fire whipped out of control in 45 mph winds on Monday, but winds were forecast to range in the 3 to 6 mph range on Tuesday, giving firefighters a chance to contain the blaze, said Brough.

He said Monday's evacuation was hampered by a failure of the county's reverse 911 system, which was down for about two hours, forcing authorities to rely on the media to get out word of the fire.

"Whether they fixed it or healed itself, we don't know," Brough said of the system.

The cause of the fire has not yet been determined.