More crews are being sent to northern Arizona to battle a wind-whipped 450-acre wildfire near Slide Rock State Park in scenic Oak Creek Canyon.

The Slide Fire has forced the evacuations of 100 threatened businesses and homes in a 2-mile stretch north of the state park, and 15 people stayed at a shelter in Flagstaff.

There are no reports so far of injuries or structures burned. Slide Rock State Park is a popular recreation area because of its natural rock water slides.

The fires in Arizona add to a troubling start for the brush fire season in the west, beginning with multiple fires in Southern California last week, including this one in Escondido, May 15. (AP Photo/Gregory Bull)

About 100 firefighters and other personnel were assigned to the fire on Tuesday, and that number was expected to more than double Wednesday.

Two Hotshot crews were assigned to the fire Tuesday, and four additional Hotshot crews and a top-level fire management team are scheduled to arrive Wednesday, Coconino National Forest spokesman Brady smith said.

A separate wildfire in the state burned 200 acres and closed Interstate 17 near Cordes Junction in both directions for more than four hours late Tuesday. I-17, which is the main traffic route between the Phoenix area and northern Arizona, reopened Tuesday evening.

The two fires sent numerous agencies rushing to fend off the blazes at a time when dry conditions have Arizona on high alert. Arizona officials are worried about the prospect of a devastating 2014 wildfire season amid a drought that has left the state with dangerously dry conditions.

The Slide Fire started Tuesday afternoon and authorities believe it was human-caused.

State Route Highway 89A is closed through the steep-walled canyon between Sedona and Flagstaff.

Red Cross spokeswoman Trudy Thompson Rice said most of the 15 people who stayed Tuesday night at the shelter at a Flagstaff school were campers.

"We had a lot more than that -- maybe 30 -- come in to register and let us know where they were," she said Wednesday.