Another day, another dense fog advisory issued by the National Weather Service in Portland for Clark County.

The advisory, which was set to expire at 11 a.m. Wednesday, lists Vancouver, Battle Ground, Ridgefield, Washougal, Yacolt and Amboy. It also includes the Portland metro area.

Visibility in some areas is down to a quarter mile or less due to the fog, creating hazardous driving conditions.

“If driving, slow down, use your headlights, and leave plenty of distance ahead of you,” the advisory says.

Traffic maps showed somewhat typical backups on southbound interstates 5 and 205 in Vancouver as of 7:20 a.m.

There was one reported crash at or near the southbound I-5 and westbound state Highway 500 junction. And another crash on southbound I-5 in Portland at Columbia Boulevard is adding to the backup.

In addition to the fog advisory, Clark County is also experiencing stagnant air conditions. The weather pattern is expected to shift by Wednesday night.