Firefighters in northern Colorado made progress battling a raging wildfire in the hills west of Fort Collins on Monday despite high temperatures, low relative humidity and gusty winds that whipped up the blaze.

The High Park Fire had consumed more than 58,700 acres of woodland by Monday evening, but it was about 50% contained Monday night, authorities reported. Residents of some homes on the east side of the fire were allowed to return home, but people from several other neighborhoods remained under mandatory evacuation orders.

More than 1,700 personnel were battling the blaze.

Michael Stillman Maher, 30, was not one of them, although he allegedly wanted people to think he was, officials said. A fire chief reported seeing the Denver man driving a truck with a stolen government license plate and carrying phony firefighter credentials in the fire area Sunday night, officials said.

Maher was arrested in a Fort Collins bar early Monday morning and charged with impersonating a firefighter and theft.