Crews say the Pole Creek Fire fire has "taken a very fast run north and to the south and east".
As a result, US 89 is closed from Pole Creek Road to US 6. Thursday, US 6 was also closed for a short time, but has since re-opened.
Wednesday night, Utah County Emergency Management evacuated homes along the Nebo Creek road to the junction with Highway 89 due to the fire.
Thursday morning the fire had burned 4,000 acres and was zero percent contained.
Further south, crews in Payson were called in to help around midnight to fight the Bald Mountain Fire. They say they were working to protect a girls camp in Santaquin Canyon but no evacuations have been ordered in Santaquin.
The canyon is currently closed.