PORTLAND, Ore. (AP) The U.S. Forest Service says a forest fire south of Sisters two months ago was probably caused by lightning.
The Pole Creek fire eventually burned on more than 26,000 acres and gave residents of Sisters a couple of weeks of difficult mornings as temperature inversions trapped the smoke.
The Forest Service said Tuesday that investigators had trouble determining a cause because the fire was intense, burning evidence.
But investigators said they determined there was an isolated thunderstorm in the area on Sept. 8 and witnesses reported lightning strikes. A large fir tree was burned, hollowed out, and broken at the base.
The investigators said the fire started in a remote area, reducing the possibility it was set.