Persistent smoke that's giving firefighters fits outside of Happy Camp, Calif. and fouling Southern Oregon's summer air could ease today with a shift of winds, authorities said.

Persistent smoke that's giving firefighters fits outside of Happy Camp, Calif. and fouling Southern Oregon's summer air could ease today with a shift of winds, authorities said.

Smoke from the 52,800-acre Siskiyou Complex fire has left moderate to unhealthful levels of particulates in Southern Oregon's air since Sunday, when winds from the southwest blew smoke to Oregon from the Happy Camp area.

Medford's air has hovered in the "moderate" category since Sunday, but has fallen short of the level considered unhealthful. The skies could get a bit of cleansing today if the prevailing winds shift and come more directly from the west, according to the National Weather Service.

"If we go back to a more westerly flow, that would be good for us," meteorologist Rick Holtz said Monday evening from the weather service's office in Medford. "We could definitely use some improvement."

An improvement in air quality is even more needed in Cave Junction, which received the lion's share of the smoke from the Klamath National Forest fire, which was listed Monday night as 36 percent contained. Firefighters estimated the Siskiyou Complex fire would be contained by Aug. 8.

Particulates in the air Monday afternoon in Cave Junction boosted the Air Quality Index to 154 parts per million. Any index report of more than 100 parts per million is considered unhealthful for young people, the elderly and people in ill health.

"So, if you're sensitive there, you really need to stay inside," said Anna Kemmerer, environmental specialist for the state Department of Environmental Quality.

The DEQ monitoring station in southwest Medford had a AQI of 81, while Grants Pass posted a late Monday afternoon AQI reading of 38. Shady Cove's AQI was 52 and the reading hit 48 at Crater Lake, DEQ statistics show.

"The readings vary depending upon where you are in the valley because of the terrain," Kemmerer said.

Closer to the blaze, firefighters and residents are working in and living with dense smoke, said public information officer Yvonne Jones at the Forest Service's Siskiyou Complex command center in Happy Camp.

Emergency crews are worried the smoke would mix with increasingly humid nighttime air to create conditions that could lead to the California Highway Patrol to close traffic along Highway 96, Jones said.

"It could end up like you're driving through pea soup," Jones said.

The Siskiyou Complex and nearby Ukonom Complex fires began from lightning strikes June 20.

The Ukonom Complex, centered around Somes Bar along the Klamath River, was listed Monday at 25,155 acres, about half the size of the Siskiyou Complex fire. Because of the difficult terrain, firefighters do not expect to have it contained until Sept. 15.

Jones said the two fires remain at least 16 miles apart. They were burning in opposite directions and were not expected to merge, she said.

Reach reporter Mark Freeman at 776-4470, or e-mail mfreeman@mailtribune.com.