Smoke from the massive, out-of-control wildfire that has evacuated much of Redding, Calif. is drifting into Oregon and the Willamette Valley, and local officials warn that the chance is increasing that wildfire smoke will blow into Portland this week.

Multnomah County health officials say "wind patterns and smoky conditions may create poor air quality this week." They point to wildfires still burning across Oregon as the source.

Meanwhile, the National Weather Service says smoke from the enormous Carr wildfire in Northern California is drifting north into Oregon's Willamette Valley, and is expected to clog Eugene today. Reports from the ground show a gray haze in Sunriver, Ore., a vacation town outside Bend.

The Carr fire started July 23, when flames spread from a malfunctioning motor vehicle. It's now 89,194 acres—about the size of Philadelphia—and has killed at least five people.

Multnomah County warns that vulnerable Portland residents—including those with lung and heart conditions, children and the elderly—should stay indoors if smoke comes to the city this week. The county health department has set up an information page on resources.

Meanwhile, it's hot: Today is the fourth consecutive day of Portland temperatures in the 90s.