Floating strands/strings of smoke on expressway?

Question

So I was coming back from Indiana to Chicago when I saw some weird string like looking things floating on top of houses and trees on the expressway. They seemed to be made of smoke, but whatever it was wasn't as dark as normal smoke. I was too freaked out to video tape it. The smoke things stayed put, they didn't move or float off as I'd expect smoke to.

Any ideas on what they may be?

Answer 1

At time smoke in a high pressure area will just hang there.