Thursday morning I drove on the main road connecting the west side to the east side, to the highest point in the park (actually, the parking lot is about half a mile and 300 feet below the highest point), the parking lot was half full when I arrived, and there were many people heading up to the observation platform at the peak (6600 ft elevation). I observed the phenomenon which led to the name Smoky Mountains, namely mist/fog rolling in and then disappearing and coming back again. The seems to be related to the high humidity and the relatively abrupt changes in elevation. Looks very much like smoke from a campfire. You can see a bit of that in one of the photos.