MEDFORD, Ore. — Freezing fog and stagnant air conditions prompted weather advisories across parts of southern and central Oregon and central Washington, creating hazardous driving conditions and raising concerns about air quality through early next week.
The National Weather Service issued Freezing Fog Advisories through noon Saturday for several inland valleys, including the Illinois and lower Rogue valleys in Josephine County, Oregon, as well as the Kittitas and Yakima valleys in Washington. Visibility in affected areas could drop to a quarter mile or less as dense fog freezes on road surfaces, increasing the risk of slick conditions.
In Oregon, the advisory covers communities such as Grants Pass, Cave Junction and surrounding rural areas. Similar conditions are expected in central Oregon, including Bend, Redmond and Prineville, and in north-central Oregon near Dufur, Moro and Maupin. Portions of U.S. Highway 97 may be especially hazardous, forecasters said.
At the same time, Air Stagnation Advisories remain in effect across the same regions, extending through Tuesday. Weather officials said a strong temperature inversion and weak winds are trapping pollutants near the surface, leading to deteriorating air quality in valley locations.
In Washington, stagnant air conditions are expected to persist in the Yakima and Kittitas valleys, including Yakima, Ellensburg and Sunnyside. Officials warned that pollution levels may increase to unhealthy levels, particularly for people with respiratory illnesses.
Health officials advised residents with asthma or other breathing conditions to limit outdoor activity and follow medical guidance. State air quality agencies strongly recommend limiting residential wood burning and avoiding outdoor burning altogether.
Drivers are urged to slow down, use headlights and allow extra distance between vehicles as conditions may change rapidly. Forecasters said improvements are unlikely until stronger weather systems break up the stagnant pattern early next week.
