The South Valley Fire was pushed by strong winds that caused it to destroy several buildings while growing to 15,000 acres.
Governor Kate Brown declared a conflagration which allows firefighters from departments across the state to respond.
The Oregon Fire Marshal's Office sent three task forces on Wednesday and three more will arrive Thursday.
Between 80 and 100 buildings are threatened and there are mandatory evacuations.
The fire was human caused, but the source of the fire won't be revealed until an investigation is complete.