GOLD CANYON -- A massive wildfire continues to burn in the Superstition Wilderness but so far is not threatening any structures.

The lightning-caused Superstition Fire started Aug. 20, has burned more than 4,400 acres and is 0% contained as of Wednesday afternoon.

Smoke and flames have been visible from the Apache Junction and Gold Canyon areas.

Tonto National Forest officials say recreation areas in northern Pinal County will be closed beginning Thursday. They will include areas west of Peralta Canyon Road, areas north of Peralta Canyon Road and the Peralta Trail.

Wednesday night the fire had spread to the northwest due to outflow winds from passing thunderstorms. This resulted in the fire backing downslope into flatter terrain.

"With the fire being in this new terrain, firefighters will now have better anchor points to engage the fire directly," the Tonto National Forest said. "This will also give firefighters better options for safety zones, and escape routes."

Officials say resource availability has been a challenge for the Superstition Fire. With multiple fires threatening human life and property, resources have been assigned to other incidents throughout the country.

The Forest Service is being assisted by Arizona Department of Forestry and Fire Management, Superstition Fire and Medical, Maricopa County Sheriff's Department, and Pinal County Sheriff's Department.

Firefighters will work to keep the fire away from structures, State Route 88 and the Lost Dutchman State Park near Apache Junction.

As of Wednesday afternoon there were no evacuations in effect for the Superstition Fire.