PORTLAND, Ore. -- Temperatures that dipped below freezing overnight Tuesday were making for a slick Wednesday morning commute throughout the Portland area.

Not just that, but commuters should mind the fog in the Willamette Valley, which should dissipate later in the morning, said KGW weatherman Brian Brennan.

"Patchy fog will be an issue for any early this morning, but east winds may help keep the Portland metro area clearer," he said. "There is currently a dense fog advisory for McMinnville and Salem and south along the Willamette Valley to Eugene. Visibility down to a quarter or a half mile."

Expect the temperature to rise to about 37 at noon and stay there throughout the day, he said.

Traffic Alerts / Latest closures

While frost and patch ice was an issue Wednesday morning, main streets and interstates were clear for the most part, due to work from crews spreading de-icer and gravel overnight all across the metro area.

Most school districts that were closed Tuesday opened their doors Wednesday, some with delayed starts.

Officials with Multnomah County say they’ve been extra vigilant about bridges and overpasses. Without ground insulating those structures from underneath, they are always the first to freeze and the last to thaw.

County spokesman Mike Pullen says, after a storm has passed, drivers, cyclists and pedestrians are often too quick to assume the danger has also melted away.

“We get out to a major street, and everything's fine, but you know the side streets, places in the shade and raised structures like bridges can be some of the last places to thaw out,” he said.

Pullen says the county only received two formal complaints about ice on area bridges. They came from cyclists crossing the Broadway and Burnside bridges.

Neither of those instances, says Pullen, resulted in injuries.

TriMet officials said all MAX lines were running with some delays, and chains were taken off all the buses. Click for TriMet alerts

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