Some areas of the Willamette Valley woke up to smoky skies Friday from wildfires burning in Oregon and Northern California.

Lake County and parts of Marion, Linn and Douglas counties are under an air quality advisory through Friday afternoon.

At 10 a.m. Friday, air quality was rated as moderate in the Salem area, reaching unhealthy for sensitive groups in some areas of the Santiam Canyon.

Much of the smoke there is coming from the Bull Complex Fire, burning north of Detroit. The fire has burned 21,191 acres and is 15% contained.

In Eugene, air quality was rated unhealthy.

The smoke was expected to clear Friday night as heavy rain moves into the area.

The National Weather Service predicts as much as three-quarters of an inch of rain overnight, with heavy rain continuing Saturday and Sunday.

The Oregon Health Authority offers recommendations for staying safe during smoke events:

Tracy Loew is a reporter at the Statesman Journal. She can be reached at tloew@statesmanjournal.com, 503-399-6779 or on Twitter at @Tracy_Loew. Support local journalism by subscribing to the Statesman Journal.