An unattended campfire grew into a small wildfire that burned the bottom of a deep ravine in the Dishman Hills Natural Area on Thursday.
Spokane Valley firefighters had trouble gaining access to the morning blaze just west of Dishman Road.
A hiker spotted the fire before it could get out of control, and reported it at 8:37 a.m., officials said.
The fire burned pine needles, woody debris, underbrush and timber.
A crew from the state Department of Natural Resources joined three Spokane Valley fire crews in the effort.
Battalion Chief Brian Foster-Dow said crews took extra time to turn over dead logs and to dig into the soil to make sure roots or rotten wood were not smoldering.
The location known as Deep Ravine is a narrow canyon about 20 feet wide.
Transient camping has long been a problem in the area, Foster-Dow said.