Parts of Oregon have smokiest air in the nation, as state issues air quality advisory that includes Portland

Warm, dry autumn weather and persistent Northwest wildfires have created the worst air quality in the nation in parts of Oregon – prompting officials to issue an advisory Friday that includes Portland and the Willamette Valley.

The Oregon Department of Environmental Quality warned that smoky air could linger into the weekend and even next work week.

The Portland area is currently blanketed in hazy air that’s blown in from wildfires mostly in southwest Washington, including the 437-acre Siouxon fire, which started three weeks ago from an abandoned campfire in the Gifford Pinchot National Forest. The air quality index reached above 100 – unhealthy for sensitive groups – in parts of Portland.

Officials recommend that young children, elderly people, people with heart and lung conditions and those who are pregnant should stay indoors.

Current air quality numbers can be found on the Department of Environmental Quality’s interactive map.

Portland’s air, however, has remained far healthier than regions to the south and southwest.

The Cedar Creek fire, which started two and a half months ago about 60 miles southeast of Eugene, continues to create the worst air quality in the country for Oakridge. The air quality index reached 500 on Friday, a level that officials consider extremely hazardous. The smoke is blowing west into Cottage Grove and Eugene, also creating levels above 150 at times, leading officials to warn that it’s unhealthy for all groups to spend time outdoors.

On Friday, the National Weather Service announced a “red flag warning,” saying gusty winds and low humidity could generate more favorable fire conditions on Saturday and into Sunday. The 123,000-acre fire is 40% contained and will most likely be fully extinguished only when fall rains arrive. But for now, daily highs remain 10 to 20 degrees above normal, though some rain is forecast in about a week.

Oregon officials issued the air quality advisory for 12 of 36 counties in Oregon: Clackamas, Multnomah, Washington, Columbia, Yamhill, Marion, Benton, Linn, Lane, Polk, Douglas and Coos. Southwest Washington officials also warned of smoky air.

Experts note that the air quality can change rapidly from hour to hour. Visit The Oregonian/OregonLive smoke forecast map here or Wildfire Tracker here to keep tabs on the latest.

— Aimee Green; agreen@oregonian.com; @o_aimee