Portland drivers should expect slick and dangerous surfaces Wednesday morning as freezing rain slowly transitions to just plain rain. In Portland, the transition is expected between 10 a.m. and noon, said David Bishop, meteorologist for the National Weather Service. Some areas in the shade or at higher elevations might take a lot longer to thaw, he said. “Overall, assume the worst in this case. Be prepared for very, very slick surfaces, whether it comes to walking, driving or what-have-you,” he said. Don Hamilton, spokesperson for the Oregon Department of Transportation, said residents should try to stay off the roads Wednesday morning to allow plows and trucks to drop salt, sand and other de-icers on the roads. “When you see a transition like that, it doesn’t happen instantly,” Hamilton said. “When the temperature rises, the ice breaks up, but the road doesn’t clear up right away. It’s not an immediate process. It takes a lot to get the ice off the roads.” He said drivers should...