While a small wildfire burning in the wilderness near Smithfield is still under investigation, the Forest Service reports that firefighters found evidence of an abandoned campfire that may have been the cause.

Firefighters have limited the Birch Canyon Fire to about 5½ acres in size, according to a release from Forest Service spokeswoman Kathy J. Pollock. The wildfire is about four miles up the canyon east of Smithfield in the Mount Naomi Wilderness area on the Logan Ranger District.

The Weber Basin Type 2 Initial Attack Hand Crew and other Forest Service personnel fought the fire using burnout operations and minimum impact fire suppression tactics. The crew is camped just below the fire and will likely continue to work in the area through the weekend.

“In addition to facing the challenges of fighting a remote wilderness fire, firefighters will also be hampered by today’s weather,” Pollock wrote. “A red flag warning has been issued for the fire area, with warm temperatures and low humidity, and a dry cold front this afternoon causing erratic and gusty winds.”

Smoke will continue to be visible from Smithfield and Cache Valley, Pollock states, and they are asking people not to report the fire.