Updated

Authorities say a small wildfire burning in the mountains just outside the Colorado city of Boulder has forced people from their homes and is filling the sky with smoke.

Wind is pushing the flames early Sunday just a couple of miles from the downtown area. The fire was only 30 to 50 acres.

Shannon Cordingly of the Boulder Office of Emergency Management says it's unclear how many homes have been evacuated just west of the university town and how the flames ignited.

The agency says there are no reports of injuries or buildings destroyed. Cordingly says if the fire keeps spreading, more evacuations are possible.

Resident Seth Frankel, who's packed after being warned he may need to evacuate, says dead trees "are exploding into a black plume that goes into the air."