Adam Spencer, The Triplicate

Major wildfires in the eastern Siskiyou Mountains continued to burn on Wednesday, covering nearly 52,000 acres, although firefighters have been able to make progress on containment.

More than 2,300 firefighters are battling the Beaver Fire near the community of Klamath River 28 miles east of Hornbrook on Highway 96 and the Oregon Gulch Fire, which straddles the California-Oregon border southeast of Ashland.

The Beaver Complex fire covered 36,723 acres Wednesday evening and was at 35 percent containment, while the Beaver Fire covered 15,230 acres at only 5 percent containment.

A lighting strike started a small fire just north of the northern fire perimeter of the Oregon Gulch Fire near Highway 66, but crews were on it, joint-agency firefighters spokeswoman Linda Brevard said Tuesday.

Oregon Gulch is the biggest of nine large fires burning across 127 square miles of drought-parched forest and range in Oregon.

Oregon Gov. Tom Kitzhaber toured the Oregon Gulch fire, the largest of 10 major wildfires in the state. While in fire camp, he called on Congress to fund more forest thinning projects to reduce the risk of wildfires.

"These fires are a symptom of a much larger forest health issue," he said. "We just have to begin to deal with the root causes. That means lending some urgency to improving the health and resiliency of our forests in away that can produce jobs.

"It's up to the United States Congress to put resources into the (forest health issue) so that we can clean up these forests and reduce this fire risk."

U.S. Agriculture Secretary Tom Vilsack this week said the U.S. Forest Service will soon have to start pulling funding from thinning projects and other programs to pay for the continued battle against wildfires.

An evacuation advisory has been issued for residents along Highway 96 in the town of Klamath River from Lumgrey Creek to Doggett Creek and on Beaver Creek Road.Highway 96 is open to local residents only near the fire area.

The Siskiyou County Sheriff's Department was preparing for the re-population of the community of Copco, which had been under level 3 evacuation.

Possible thunderstorm activity on Wednesday night held the potential to start new fires and cause erratic wind behavior that could affect the spread of the Beaver Complex Fire.

"We are not out of the woods yet," Mark Ghilarducci, director of the California Office of Emergency Services, said Tuesday.

The Associated Press contributed to this report.