Fire officials in Utah County have evacuated residents from homes in and at the mouth of Provo Canyon after a fire sparked Saturday afternoon and has continued growing.

The blaze — called the “Range Fire” — began around noon above Orem, near a gun range. State fire officials first estimated it had burned 15 acres. By 4:30 p.m., it was 300 acres and had grown to 1,500 acres three hours later. It was 0% contained.

Shaun Hirst, with Orem Fire Department, said he expects crews, using helicopters and other aircraft, will be trying to extinguish the fire for days and that some homes in the area are under a “direct threat."

Homes on Squaw Peak Road, south of Provo Canyon, have been evacuated, as well at the homes at the mouth of the canyon and hunters in the area, as the fire moved east Saturday. U.S. 189, which leads into the canyon, was also closed.

Hirst said investigators are looking into the fire’s cause, but said Saturday evening that it’s unclear how it started. He noted people were training at the fire range about the time the blaze started.

By Saturday evening, fire crews had burned the vegetation and other fire fuels behind the homes at the mouth of the canyon to try to stop the wildfire from spreading.

Another wildfire started in Summit County on Saturday, the 1,600-acre Fire Canyon Fire. Officials have said it is “human-caused.”

The blaze started between Echo and Henefer, east of I-84, and isn’t threatening any buildings.

However, the fire did force Utah Division of Wildlife Resources to evacuate hunters from the Henefer-Echo Wildlife Management Area on the opening day of the general-season rifle deer hunt.

The division said some of those hunters were the first to report the fire when it began on a ridge between Bald and Fire canyons.

The wildlife management area will be closed until further notice.