At least two people were arrested as Chico police broke up a crowd of several hundred that had gathered around a bonfire on a residential street.
One woman was treated for minor burns after the drunken disturbance early Friday near California State University, Chico.
Authorities say 200 to 300 people gathered around the fire at Sixth Street before midnight Thursday, adding a couch and other items to the blaze.
Police blocked off several streets, but the crowd refused to leave, throwing rocks and bottles into the street. The area was quiet by 1:30 a.m. Friday.
It’s unclear what prompted the gathering. Some witnesses said nearby house parties may have spilled into the street, while others say it was to mark the first week of the new semester.