An approximately five-acre fire is burning west of Colfax, according to Cal Fire. The fire started near Dog Bar Road and Venus Court on Thursday afternoon. Firefighters say the incident started as a structure fire that spread to the vegetation. Officials said possibly a motor home and outbuilding is involved. A volunteer watchman spotted the fire and alerted firefighters. Aircraft resources have responded to aid in the firefight. No injuries have been reported. Firefighters said they made good progress on the fire and were canceling extra resources around 4 p.m.