The National Weather Service issued a dense fog advisory Tuesday morning for the Portland-Vancouver area.
The advisory is set to expire at 10 a.m.
The air is clear near the Columbia River, but Vancouver is included in the affected communities. Fog is also present in the Clark County cities of Battle Ground, Ridgefield, Washougal, Yacolt and Amboy.
Visibility is reduced to a quarter-mile in some spots around the county, according to the weather service.
“Motorists should be prepared for abrupt changes in visibilities over short distances when traveling in the Willamette Valley including stretches of Interstate 5,” the advisory said.
Drivers are being asked to slow down. A two-vehicle crash on the Interstate 205 Bridge is blocking a single lane of traffic on the freeway as of 6:50 a.m.
